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Stbmfjj Annual Juport

OF THE

AERONAUTICAL SOCIETY

GREAT BRITAIN

FOES THE YEAR 1872,

PRINTED BT

HENRY S. RICHARDSON,

GREENWICH,

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ll/l permission of the Royal Aeronautical Society

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THE

AERONAUTICAL SOCIETY OF GREAT BRITAIN.

Prcgfocnt,

HIS GRACE THE DUKE OF ARGYLL, K.T.
UicE-Ipre«it)entg,

HIS GRACE THE DUKE OF SUTHERLAND.
RIGHT HON. THE EARL OF DUFFERIN.

LORD RICHARD GROSVENOR, M.F.

^anomro Secretary,

FRED. W. BREAREY, Esq.

^oaoratu Solicitors,

Messrs. MATTHEWS & Gl^EETHAM, 26, Bedford Row, w.o.

(Council,

A. ALEXANDER, Esq., C.E., M.A., Sheffield.

FRED. VV. BREAREY, Esq., Maidenstone Hill, Blackheath, 8.E.
Sir CHARLES T. BRIGHT, F.K.A.S., Lancaster Gate.

CHARLES BROOKE, Esq., ALA., F.R.S., 16, Fitzroy Square, W.
JOHN BROWNING, Esq., F.R.A.S., F.R.M.S., 111, Miuories, E.
HUGH W. DIAMOND, Esq., M.D., F.S.A., Twickenham.
JAMES GLAISIIER, Esq., F.R.S., F.R.A.S., Blaeklmath.
Rear-Admiral Lord JOHN HAY, C,B 119, Piccadilly.

W. H. LE FEUVRE, Esq., C.E., F.lt.G.S., 68, Bedford Gardens,
Kensington, W.

MAGNUS OHREN, Esq., A.I.C.E., Lower Sydenham, S.E.

Lord LINDSAY, 47, Brook Street, W.

F.'H. WENIIAM, Esq., C.E., V.P.R.M.S., Padnal Hall, Chad well,
Essex.

HENRY WRIGHT, Esq., Stafford House, St. James’.

WITH POWER TO ADD TO THEIR NUMBER.

Member’s Subscription, XI. Is. per annum, dating from the day of Election.
Ladies may become Associates upon the same terms.

<$*b.entjj Annual $3Upod

OT THB

AERONAUTICAL SOCIETY OF GREAT BRITAIN,

FOR THE YEAR 1872.

Containing an Account of the Proceedings, and a Selection from the
Papers and Communications* received by the Society during the
year, with concluding Remarks upon the present state of the
Science.

A General Meeting of the Members of this Society was
held in the Theatre of the Society of Arts, John Street,
Adelphi, on Tuesday evening, the 18th inst. Mr. James
Glaisher, F.R.S., presided.

A new machine, constructed under the direction of the
Society, for measuring the relation between the velocity and
pressure of the wind, was exhibited.

At the request of the Chairman,

The minutes of the previous meeting were read by Mr.
F. W. Brearey, the Hon. Secretary.

* The Council, in publishing any paper which may have been
read or communicated, disclaim any intention of endorsing the views
of their respective Authors. It is with the bolief that here and there
a hint may be conveyed which may prove of use to those of the
members who may be practically engaged in overcoming the
acknowledged difficulties of the problem to be solved, that some of
the papers have been published, which otherwise would appear hardly
to justify their reproduction.

AERONAUTICAL SOCIETY

The Chairman : Ladies and Gentlemen, — the subject
which wall most naturally attract our attention this evening,
is that of the experiments which have been made by the
apparatus now on the table before us. I had almost forgotten
that at our last meeting we spoke of this instrument having
been designed. It was not completed so soon as we expected ;
and, although much time has been occupied in making
experiments, the results are not quite so conclusive as could
be desired ; but so far as they go are important — not only in
respect to the problem we wish to solve, but, as bearing upon
the pressure of the wind on the surfaces of planes. I will not
now engage your time longer, but I will ask Mr. Wenham,
under whose core, in conjunction with Mr. Browning, the
experiments were carried out, to give a statement respecting
the results. It is an instrument of a kind which I have .long
desired, and it seems calculated to achieve what we require
in this direction with greater accuracy than any other instru¬
ment I know. I call upon Mr. Wenham to explain the
apparatus.

Mr. W f.nham expressed his regret at the absence of Mr.
Browning, who had been associated writh them in these
experiments. To make this instrument understood, he
would explain how it acted as an ordinary anemometer, for
ascertaining the direct force of the wind on a plane, when in
a vertical direction to its surface. This consists mainly of a
vertical steel spindle, supported on a hardened steel centre.
Through an eye at the upper end of the spindle, a horizontal
arm passes, and is secured by a small cross-pin, which allows
the arm to vibrate like the beam of a balance. The long
end of the arm carries the planes ; and the opposite short
one has a sliding counter- weight, which is adjusted so as to
exactly balance planes of different sizes at the long end of
the arm. Each plane is clamped at the end of a tail rod,
which is pivotted through the forked end of the arm, by a

OF GREAT BRITAIN.

vertical steel pin, as close to the plane as possible; the
other end of the tail passes loosely through a vertical slot,
slightly curved as a radius, from the balance centre of the
arm. By this arrangement, the surface of the plane is
always kept at right angles to the current, throughout the
extent of its horizontal motion. A wooden shield is fixed
close before the front of the arm, to protect this and the
balance weight from the wind, so that the planes only may
be exposed to its force. The action of the instrument, as a
single anemometer only, or when the planes are set at right
angles to the current of air, is obvious. The direct pressure
is read off by the spring steel-yard, which is connected to
the end of a lever from the vertical spindle, close to the base
of the machine. In order to measure the vertical forces, the
plapes are set at the requisite angles from a divided sector,
whose centre coincides with 'the clamping screw at the back.
The raising force due from the various inclines, was read
off by the upright spring steel-yard. It was found almost
impossible for one observer to read off the horizontal and
vertical forces simultaneously during fluctuations, therefore
the readings were noted by two persons at a given signal —
even this was a matter of some difficulty. The arrangement
would be far more useful and perfect as a scientific machine,
if fitted with a piece of clockwork, moving a paper cylinder,
on which the vertical and direct forces would be simul¬
taneously registered by separate pencils, describing two
undulating lines, showing at a glance the relative forces ; the
experimenter would then have nothing else to attend to, but
to see that all other conditions were acting properly.*

The Chairman : I think the remarks by Mr. Wenham
important, especially with regard to the effects produced
on the planes at different inclinations. When the plane

* The tabular statement of the experiments referred to, were
published in the Annual Report for 1871.

AETtONATTTICAT, SOCIETY

was placed vertical, the pressure of the blast of air was
direct, and tended only to move the plane in a horizontal
direction — being that of the dii'ection of the air itself —
but when the plane was inclined, a part of the pressure
was exortc d in raising the plate in a vertical direction,
and a part only in exerting a horizontal pressure ; so that
the latter was less than in the previous case. When the
plane wac placed at an angle of 45°, the horizontal force
and the vertical force were found to be identical, as mentioned
in the manner described by Mr. Wenham. It was also found
that whether the exposed surface was a circle, a square, or a
parallelogram, providing the area was the same, the results
were identical to the degree of accuracy to which the
readings could be determined. Anyone who had not
considered with care the nature of the pressure produced by
the flow or rush of a fluid, elastic or incompressible, against
a plane surface placed in its course, might imagine that the
system of parallel forces was merely equivalent to a single
resultant force acting at the centre of pressure, and capable
of resolution according to the ordinary parallelogram law.
But this of course is not the case, for the particles of the
fluid which come in contact with the plane, have somehow
or other to get out of the way, by gliding along the surface
of the plane (as they cannot get through it), and this produces
a complication in the neighbourhood of the surface of such
a hind as cannot be theoretically predicted. One thing,
however, is quite clear, and that is, that- the directions of
all the small forces acting on the surface certainly are not
parallel, and that we must therefore have recourse to experi¬
ment. Even the fact that when the inclination of the plane
to the current (supposed moving horizontally) is 45°, the
vertical and horizontal pressures are equal, is not by any
means evident ; nor in fact can it be exactly true ; for
supposing (to fix the ideas) that the upper part of the plane

OF GREAT BRITAIN-.

is bent over so as to point in a direction opposed to that in
which the current is moving, and making an angle of 45°
with it, then most of the particles of air in the vicinity of
the plane will, in order to get out of the way, be moving
downwards along its surface ; so that compounding this
motion with that of the current, we should expect the
horizontal force to be greater than the vertical. The
experiments have shown that this difference is not appreci¬
able to the extent to which the instrument can measure it.
The same qualification also must be understood to apply to
these results, from which it would appear that the pressure
was independent of the form of the surface. The velocity
of the current in these experiments, was measured by a
Lind’s Anemometer, an instrument that has never appeared
to me to give very satisfactory results ; but still the only one
available for the purpose. I regret that the apparatus is
considered by Mr. Browning to be too delicate to be used in
the open air, but I hope that this will not be always found
to be the case. As I have said before, difficulties exist
only to be overcome, and some day I trust, we may obtain
a series of experiments, in which ordinary wind will replace
the use of the artificial current. I see Mr. Brooke present,
who helped us with the experiments, and he may be able to
say something as to the results gained.

Mr. Brooke said it was not exactly mentioned, but the
fact was notorious to everyone acquainted with mechanics,
that in whatever position the plane was placed, the horizontal
pressure may be resolved into two — one perpendicular to the
plane, the other in the direction of the plane. It was clear
that the resolved pressure acting in the direction of the
plane was wholly effective in raising the plane. The resolution
of the pressure into two, was well known to everyone
acquainted with the principles of mechanics ; but it was to be
understood that there were many other facts to be considered.

A.ERON ATTTICAIi SOCIETY

The simple geometrical consideration of the action of the
pressure upon the plane, did not involve the necessity for the
particles of air which had impinged upon the plane, getting out
of' the way to enable other particles to impinge upon it. This
led, in this experiment, to a result which might have been
expected, but which it was important to ascertain. There
were two rectangular planes of the same shape and area, and
one was capable of being inclined lengthwise, in relation to
the wind, and the other crosswise. Supposing the wind to be
coming in a given direction (indicated as being towards the
speaker) it was quite clear, with the plane inclined lengthwise,
there would be less surface of the plane impinged upon, than
there would be in the transverse direction (indicated on the
instrument). The particles which impinged upon the former,
must move along the plane, and had much more difficulty in
getting out of the way, than particles which impinged on the
plane in the latter position. This would show that the effective
pressure of the wind at the same velocity was greater upon the
one plane than upon the other. And, conversely, a revolving,
or oscillating plane, moving in the former direction (indicated),
would move with less force than in the latter direction
(indicated). And here was an illustration connected with the
wings of birds, particularly of those that had powerful flight
— -where the wing was exceedingly long and narrow, it
struck the wind in that direction (indicated). The experi¬
ment showed that from the same amount of surface, there
would be greater effect upon the air by a long narrow wing,
than by a short and broad one of the same area. That was one
of the results that had been obtained by these experiments.

Mr. Wen ham : I partly neglected to show how this
illustrates the flight of birds. You will find that the lifting
power of the smallest angle is nearly five times that of the
direct force. We were not able to try less angles. The
smaller the angle of inclination, in regard to the current, the

OF CHEAT BRITAIN".

less the direct force ; and, comparatively, the lifting force is
scarcely diminished. At 15 degrees, one force is nearly five
times that of the other.

Mr. Harte asked if, in making those experiments,
attempts were made to ascertain any pressure of the wind
downwards.

Mr. Wenham: No! I omitted to mention that. A
spirit level was laid across, so as to level the instrument.
We had a trunk twelve feet long and eighteen inches square,
to direct the current horizontally, and in a parallel course.

The Chairman : Certain conditions of current were tried
by Lind’s Anemometer.

Mr. Haute : Did you notice, in making these experiments,
where the centre of pressure came ?

Mr. Wenham : We were not able to ascertain very accu¬
rately. In all cases there was a tendency to lift the front edge.

Mr. Harte : Did you notice whether, according to the
angle, the centre of pressure came forward?

Mr. Wenham : We found as the angle became more
acute, the centre of pressure came nearer to the front edge.

Mr. Hall (of Acton) : Was the experiment made with a
surface larger than one foot ?

The Chairman : We had one eighteen inches square.

Mr. Hall : A different result would, I think, be attained
with two feet, from wh it was attained with one foot.

The Chairman : We have not spoken of two feet, because
the shaft was scarcely large enough to give the even
pressure required. We did not feel quite so certain with
respect to large planer ; and, therefore, the experiments with
them are not included in these records ; but I am ready to
believe that the larger the planes, the larger the results.
With areas of six inches, twelve inches, or two feet, the
larger area, the larger are the relative results. I have
had three or four anemometers together, and always found
this to be the case.

12 AERONAUTICAL SOCIETY

Mr. Brooke : I rise to make an explanation. The 0 in
the return ought to be 90. It ought to be 15, 20, 45.
and 90.

Mr. F. W. Brearey (the Secretary) : If there is any
gentleman here who could give us any advantage with
regard to a fan-blower, we should be glad to avail ourselves
of it. The area was so small, that we could not expose
much surface.

The Chairman : But we ought to give our thanks to Mr.
Penn, for the blower he lent to us, and for the use of his
steam power. The entire work of the shop was stopped,
during part of the time we occupied it. I should like to ask
you to thank Mr. Penn, for the facilities he gave us on that
occasion for making these experiments. (Applause.)

Thanks were accorded to Mr. Penn by acclamation.

The Chairman : I have now to introduce to your notice
a gentleman who, I believe, has travelled more than 100,000
miles, and has visited New Zealand, California, and many
other parts of the globe. Wherever he has been, he has
watched as much as possible the flight of birds, and, as the
result of his observations, he thinks it possible for man also
to obtain flight. He knows New Zealand as well as he
knows London, and he is now about to give us the benefit of
some of his observations. We shall, I am sure, be glad to
receive them. (Hear, hear.)

Mr. Head (the gentleman referred to) read a paper on

“ Flight."

“ Flight is performed by birds, insects, mammals, and to
some degree by fish ; and long ago, in an old period of our
world’s history, by dragons.*

“ Gliding down inclined planes is not true flight — because
it must be very limited, and requires altitude in proportion

* Pterodactyls ♦

OF GREAT BRITAIN.

to length of horizontal distance. Still, animals possessed of
the power of true flight, make great use of this advantage.

“ Flight is performed in straight lines, and curved lines ;
and the curved lines may he of two kinds — the upward
curved line of the flying-fish, and the downward curved line
of the yellow-hammer and albatross. Bees, beetles, dragon¬
flies, cockchafers, and blue-flies fly straight — so do rooks,
pigeons, ducks, and shags, and many other birds. Beetles,
cockchafers, albatrosses, and ofttiraes hawks, ily on aero¬
planes, or under them rather, and are propelled in the desired
direction, in the case of beetles and cockchafers, by their
true wings blowing in the other.

“ How albatrosses fly I do not exactly know. Weight acts
on a flying-fish directly he leaves the water, and also his
inability to keep up his speed ; and so, by the law of con¬
tinuity it describes an elongated curve, with some slight
contortions, caused by working its aeroplane fins.

“ A large flying-fish, about nine inches long, rose close to
our weather-bow, and flew into a wave and rose again ; it
then flew nearly to windward a long way, and three times
gave itself a fresh impetus by sculling its tail in the top of a
swell ; so that the fish was not lost to my view, though some
distance off.

“ A dragon-fly has two pair of movable wings, and can
dart about backwards as well as forwards, and it can also be
quite still seemingly on the air. Bats fly in a most erratic
course, but that only proves what command they have over
their powers of flight, and is not a sign of weakness. So
that besides the true manner, there are two distinct modes
of flight — one, with an aeroplane, as the albatross, beetle,
and hawk — and the other without, as sparrows, flies, and
bats.

“ Flight, as it is performed by the non-aeroplane flyers, I
leave, as being by far the most difficult to be achieved by us,

AERONAUTICAL SOCIETY

and as requiring not only an exact balance between the
wings, but also an exact stroke equal to the weight of bird,
and each wing equal to the other in direct line flight — the
upstroke also being so regulated that the under-current of air
is exactly equal to weight of bird — the down-stroke being
the propelling blow, by blowing wind, or the air, in a direc¬
tion the more opposite to the line of flight the better ; as,
if a fair blast blows ten pounds to the foot, and it be free in
mid air, it would be driven in a contrary direction, with a
force of ten pounds to the foot area of blast aperture, and if
it presented five feet of area to atmospheric friction, it would
be driven forwards at the rate of sixteen miles an hour.

“ Sky-rockets fly straight, only perpendicularly to still
water — in any other direction they are drawn — by their
weight, or, as it is called, the alteration of gravitation, more
and more down, till they strike the earth ; but if they had the
ears of a bat, or balancers like a fly, or a small fin aeroplane
set to the exact angle, to suit their line of proposed flight, and
the force employed, they would fly straight in any direction
whatever — so long as the force was even and equal, and the
wind did not vary ; and, then, a sky-rocket is a flying
machine of the cylinder blast kind, and for the time carries
its power with it — but, as it continuously gets lighter, of
course it could not be set to go quite true. A steam-engine
might be made on the same plan, with one end of the
cylinder out, but it requires a great supply of steam, and
could not be made to go far.

And now I come to consider aeroplane flight, and the
best mode by which it can be attempted by man ; and —
First, there must be three indispensable requisites, without
which, it cannot be performed — weight; of which I need say
no more, as that is easily obtained — but that without it, the
machine might be any way up, and be carried about
by any puff of wind. An aeroplane suspender, and a

OF GREAT BRITAIN.

force as a means to effect speed, or speed multiplied
by depression of air, equals weight — for horizontal
flight, and is so much greater for any angle upwards,
to sixty degrees of altitude, above which an aeroplane could
not be of much use. The great enigma is the necessary
force to ensure a certain amount of speed to a plane surface,
set to a certain angle, according to that speed, and with
spread enough to drive down or press down air equal to the
amount of weight of the whole machine and driver.

“ Can it be found? that is the question. And what is the
amount of force requisite ?

“ Suppose that he is drawn up an inclined plane of any
angle, and that the friction is nil.

“ On a level, it would require but a few pounds, except to
start ; scarcely anything in fact. At the angle of thirty
degrees, it would require about one-half of half a horse, or
one quarter ; and twelve degrees, about half that, or one
eighth. But we will reckon that a man and machine, at
200lbs., would require -100 x 16 ~ 6400 foot pounds per
second — or rather more than } horse power, to raise per¬
pendicularly — that is, it would take one ordinary man and
one-sixth of a man, to raise his own weight, and the balance of
the 2001bs., sixteen feet, in the second of time, by any means
at his disposal — without reckoning friction of atmosphere.
To raise it twice as quick, would require four times the
power, or nearly one-horse power perpendicularly — that is,
at the rate of twenty-one miles an hour.

“ But we do not want to fly straight up, nor above an
angle of thirty degrees ; which would not take quite half
the powers of perpendicular ascent — excepting the friction
which, on an aeroplane, you may count for nothing — (I am
not now speaking of the friction of atmospheric resistance).
And at an angle of ten degrees, about one man power would
be sufficient to drive an aeroplane machine twenty miles an

AERONAUTICAL 80CIETT

hour ; which, I consider, to be very well, for it would not
often be required to mount even at that grade — and once up,
one could easily go on level.

“ I have not, however, taken into consideration the force
required to drive the machine through the air.

“ To drive one foot through the wind or air, at the rate of
fourteen miles an hour, requires one pound of force ; and, at
the rate of twenty miles an hour, two-and-half pounds to the
foot; and, reckoning the vertical area of the machine, man,
and all at thirty feet, it would require one-fourteenth of a
horse-power, or less than a half of a man to drive it through
the air at the rate of twenty miles an hour.

“ And now the conclusion is, that a man could not raise
himself on a machine, by his own exertions, at a greater
angle than about eight degrees of grade, and at no much
greater speed than twenty miles an hour — but even if that
can be done, it would not be a bad beginning.

“Flying will become a business, and not every one could
attain to it ; nor would it be desirable.

“ But flight by steam will be achieved yet An engine of
1-horse power could drive 1000 pounds up an incline of
about 1 in 10, with proper appliances.

“ Now for the appliances ; calculating that a man — a
gymnast at any rate — has power enough to sustain himself in
horizontal flight an hour, and that he is the power obtained,
and also the guiding will — having the weight and power— all
we want is the aeroplane, and a means by which this power
can exert itself in the air — in fact r machine, and one that
can be kept in any proposed direction, and right way up.

“ Before considering that, I should like you to direct your
attention to an arrow, or to the long rod of a sky-rocket, or
the tail of a peacock, or bird of paradise, and to the long
body of dragon-fly.

“ In the case of the arrow and skyrrocket, they are both
kept in their places, or line of motion, by a light long drag

OF GREAT BRITAIN.

behind, as a steer-oar, and that is the best form for us to
make use of at present, with weight forward.

“ Twenty miles an hour is a low speed, and is reckoned to
an angle of eight degrees, but horizontal flight could be
maintained to many times that speed ; and it entirely depends
on the speed that can be obtained what size of aeroplane is
required, and also the shape of it. The greater the spread
the more air is passed over that has not been deflected
downwards by the fore part of the aeroplane ; and so, for
the same reason, a wide one is useless, that is long in the
line of flight. So an aeroplane, or rather the pair of aero¬
plane wings, must be long and narrow — say twenty feet each,
and three feet wide, or even less— about two and a half,
or two — rather more than the proportion of the wings of, an
albatross.

“ Also, a short bevel in the line of motion is easily regulated
by an aeroplane lever, while a large square surface is only so
regulated with great difficulty.

“ And now for the last consideration. How is the force to
be applied ?

“ Whatever any one may say to the contrary all forward
motion in flight is performed, or effected, by blowing in the
other direction, and is the only way of doing it, as in
swimming; and that can be done in many ways, as, a pair
of bellows, a drum blast, or screw fans, or wing fans, or a
fluke or common fa—

“ A whale can nearly lift himself out of the water by the
accumulated momentum gained by a fluke fan in the water.

“Now a fan blast can be constructed to blow, say one
pound to the inch — but say lOOlbs. to 1 foot, which gives a
rate of 140 miles an hour to l foot, or about 25 miles an
hour to 33 feet of exposed area of vertical surface.

“ But as the machine would have to run on wheels in
order to gain momentum to start, the handiest mode for us

AERONAUTICAL SOCIETY

to make use of is to construct the pair of back blowing fan
propellers of a size according to height and width of
wheels, worked by a bevelled pinnace set to corresponding
bevelled cog wheels inside the two driving wheels.

“ So the whole machine may be described as a simple
velocipede, with the two driving wheels in front, and of
rather large size, held up by a supporting canopy over the
driver (which is not absolutely necessary), and two narrow
long wing aeroplanes, slightly elevated, and bent like an
unstrung bow, and kept in direction by a long steer oar with
a broad horizontal plane and a narrow vertical one.

“ The steer oar to work on an universal joint, and the
tiller to end in an oval ring, to encircle the aeronaut, allowing
it also to work the small steering wheel aft.

“ I wish now, in conclusion, to say a word or two
concerning the albatross, because I consider that it is the
best flier in the world. He always lives in a half a gale,
the great Southern Cyclone, and round and round the Pole
he glides on his way. He has been caught seventeen feet
from tip to tip, and I am sorry to say that I never heard
what one weighed, or his measured area of spread of wings ;
but I feel quite sure that as a pendulum takes but the
slightest force to make it rise to the level from which it fell,
so does the albatross fall from a height, and skim along and
rise again to about a level with the point of departure, and
so it flies on in, I think, parabolas downward, and with
scarcely even a flap will keep with a ship travelling nearly
three hundred miles a day, and coming and going for miles
round all the time three thousand miles in a week.”

In the course of the reading, Mr. Spencer exhibited a
miniature model of a boomerang, which he discharged from
a spring, exhibiting the gyrations of the instrument in the
air, and its return to the point of discharge.

On the conclusion of the paper,

07 GREAT BRITAIN.

Mr. Moy, advancing to the black board, explained by the
use of diagrams, the adaptability of Mr. Scott Russell’s
wave line to aerial machines. He said that he had studied
ship-building in former years, and he thought that the
knowledge so gained might be useful to aeronautical science.
What they wanted in making the bow of a ship was to shunt
the water off easily to the bend of the vessel. By using Scott
Russell’s wave-line, they found that they did no more work
than they wunted. If they tried the same principle of
the wave line by that instrument, they would tind that
whether the plane were long or short they got the same lifting
power. Some gentlemen supposed that a cup surface would
do better than that, but it would not. He should like to see an
experiment tried on these planes if they could get a current
of air blown upon them ; at the same time it would be better
if they could get it tried outside. It would be better if they
could get the instrument attached to a railway- train going at
great speed, that might serve their purpose more effectually
than blowers. When they came to flying machiucs they
wanted to get very tine angles. The coarsest angle he would
like would be 5 degrees. At these fine angles the wave line
curve was almost flat ; but if they could accommodate those
machines to the wave line it would be better than being
quite flat. He mentioned this in order that those who were
trying experiments might bear it in mind.

Mr. IIarte would like to ask Mr. Head, who had had such
a large experience, if he had observed any difference between
birds when flying through calm air and when in a storm.

Mr. Head said that it was scarcely ever calm in the
habitat of the albatross.

The Chairman said that would lead to the inference that
the stronger the wind the more easily the bird moved
through the air, and that the action would be different in a
state of calm from what it would be in a gale.

AERONAUTICAL SOCIETY

Mr, Head was not sure that the albatross could fly save
in a gale.

Mr. Wenham could not agree with' the statement that a
bird’s weight can act as an abutment, or a persistent force,
in helping to sustain it in one direction against the wind,
like the string of a kite ; or that the constant winds of the
Southern Ocean are at all necessary to keep the albatross per¬
petually on the wing without effort. The bird is sustained by
skimming over a vast body of air which may be in rapid
movement against the earth, but with respect to its own
condition is stationary. It may be a fifty-mile current, and
if the bird make that speed in flight, in the direction from
which the wind comes, it will make no progress relative to
the ground, but in the opposite direction will speed on at
the rate of 100 miles per hour ; yet its progress through the
body of air will be identical in both cases, or fifty miles
per hour ; and the conditions of flight are alike and the
same as in still air. After the first abutment, spring, or
momentum has been obtained, and the inertia from the
earth expended, it ceases to exert any influence, and might
be any distance off, or not there at all, as its presence does
not affect the result. It was, therefore, a great mistake to
suppose that the albatross was sustained in the air on
account of currents prevailing in any one direction. The
bird would exist in the same relation to the air as if it were
in a calm, just as a balloon drifted along independently of
the earth. It would be quite insensible of the current.

The Chairman : But the balloon goes with the wind —
that I know to my cost (laughter). The bird goes against it.

Mr. Wenham : The bird with the wind will make 80
miles an hour; but, relatively, it would make the same,
either one way or the other.

Mr. Head : I may make the remark that water in motion
will carry big stones.

OF GREAT BRITAIN.

Mr. Wenham : There is a mistake. You throw a big
stone into a rapid current, and it sinks to the bottom in a
moment, and you will only see it bound and rebound as it is
rolled along.

Mr. Head said that Canterbury Plains (New Zealand)
were formed by boulders which had been brought down by
the river. The whole of the West Coast of New Zealand
was formed in the same way.

An Hon. Member : But those stones are at the bottom.

Mr. Moy : That is just the resistance of two elements.
We might as well speak of a tile which was blown down in
front of my house last January.

Mr. Stuart Harrison thought that with regard to that
bird, the albatross, we had not got quite at the truth yet.
The weight of the bird had, in his opinion, a great deal to do
with the fact that it was sustained in the air. The weight
of the bird served the same purpose as the string of a kite.
Take the case of a balloon. The balloon had no gravity, no
tendency to fall ; but it simply floated as a piece of wood on
water. Now take the case of the albatross. The wind
impinged against the wing of the albatross, and, supposing
that the bird had no gravity whatever, it was clear that the
force of the wind on its wing would drive it more and more
in one direction. The bird would continually rise ; but the
fact that the bird had gravity, enabled it to fly in another
direction, at a fixed position, relatively to the earth. At that
position the bird would remain over a fixed spot, with out¬
stretched wing, because the current of air and the tendency
of the bird to fall would counterbalance the elements of
motion. Change of position would give that motion which
the reader of the paper had so graphically described as a
movement of the wing.

Major Robertson had seen many albatrosses fly, and
quite agreed with the observations just made. With the

AERONAUTICAL SOCIETY

albatross, it was easier to fly in a gale of wind than a calm,
because of its very great weight.

Mr. G. J. M. Hardingham was not quite satisfied about
the albatross. Illustrating his remarks by lines and curves
on the black board, he explained the action of the force of
the wind, and the counter-balancing power of gravity as
affecting the flight of the bird. But it was a mistake to
investigate this albatross question so much. The action of
a crow’s wing would much more forcibly illustrate the action
of a bird in flight. Instead of looking at extraordinary
flyers, such as the albatross, they should take a simple flyer,
and if they could explain that they could get at the other.
A great deal of the different kinds of flight could be explained
by the angular set of the wing — (explained on the board).
Judging from his observations of the effect of the down
strokes of the wing in sustaining a bird, he worked it out,
and found that for a machine to lift one man the horse-power
came to about twenty horse-power ; so that the chief
objection was, they would have to get a very strong man
indeed to work a machine for the sake of lifting himself.
The fact was, that the forward resistance was a mere bagatelle
compared with overcoming the gravity. The great thing
was, therefore, to overcome the gravity.

Mr. Hall remarked that birds of the crow kind very
rarely soared about, or sailed with the wing in a motionless
condition, as the albatross and birds of larger powers of
flight. These larger birds brought their weight greatly into
play to enable them to hold their own against opposing
currents of wind. He believed, therefore, that wdien flight
by human beings was brought into operation it would be by
bringing the weight of the machine into play as a balancing
power. It was weight that enabled the condor to fly
many miles in a few minutes, without any motion of his
wing, in the elevated region of the Andes. This could not be

OF GREAT BRITAIN.

obtained by any other means than weight. He had been
brought to this view some years ago by observing gulls flying
on the seashore. He noticed that they kept themselves
suspended simply by bringing their weight into a state of
equilibrium, and always keeping their head to the wind.
He had formed many models upon this relation of weight and
equilibrium. First, he formed them on the plan which Mr.
Moy deprecated — the cup shape — but he found it better
afterwards to adopt the wave-line stem for his embryonic
flights. He was convinced that the wave-line was the right
principle, and he was trying to bring it into action. His
great difficulty was to get an opposing current of air strong
enough to get the machine away from the earth. Dr.
Pettigrew, in the current number of the Natural Science
Review , had adopted the same view. He would ask the
gentleman who read the paper, and who spoke of “ flittering
flight of bats,” whether he had not seen large bats fly almost
like the albatross, in a straight line.

Mr. Head : I have heard of them, but I never saw them.

Mr. Brooke thought there could be no doubt that a bird’s
wing did assume the wave-line in flight.

Mr. Arthur M. Saunders asked whether the wave-line
was intended to increase or diminish the resistance. It
appeared to him that with an aeroplane the object was to
increase the resistance so as to give more lifting power.

Mr. Moy remarked that if they wanted to send a ship
rapidly through the water they would adopt the wave-line ;
but if they wanted her to go down, they would adopt another
shape. The wave-line got rid of the resistance forward.

An Hon. Member suggested that some experiments
should be made on the wave-line principle.

The Chairman : That will be another class of experiments.
The great thing was to connect pressure with velocity.

Mr. Hardingham would like to know how velocity was
measured.

AERONAUTICAL SOCIETY

The Chairman: It was not measured. The experiment
was merely by pressure on the surface. We have no idea at
the present moment of the connection of pressure with
velocity : it probably varies as the square. But I did hope
we should have been able to get some results to-day,

Mr. Hakdingham remarked that resistance was according
to the sine. It was nearly the square of the siue.

The Chairman : There is one duty we have to perform.
It is fortunate that this gentleman has been travelling in
those regions so far and so long, and it is still more fortunate
that he has come to give us, in the simplest language he has
been able to use, the results of his observations ; and I am
sure you will thank him for what he has done (hear, hear).
He has not only seen, but has reflected ; and has put his
thoughts into shape, and given them to us. I therefore ask
you to thank him for his paper.

Carried by acclamation.

Mr. Head acknowledged the compliment.

The Chairman remarked that he had still a paper,
written by Mr. Gosling, C.E., of Bombay, but it would be
for the meeting to say whether at that late hour they would
hear it, or would reserve it for a future meeting.

On the question being put, the latter course was approved,
and, after passing a vote of thanks to the Chairman for
presiding, the meeting adjourned.

OT GREAT BRITAIN'.

The paper published in the last Annual Report, con¬
taining extracts from “ Lectures on the Phenomena of
Flight in the Animal Kingdom by M. Marey, of the College
of France, was translated and contributed to the Society by
Mr. T. J. Bennett.

A more detailed translation has been called for, in
compliance with which we must almost absorb, if not exceed,
the space allotted to the Annual Report for 1872 : —

The Movements of the Wino of Insects.

* * * * * *

We have begun to study the motions of the wings, and the first
question which presents itself is the frequency of these motions. On
this point direct observation is of little assistance ; the acoustic method,
which consists in determining the frequency of the strokes of the wing
by the pitch of the buzzing of the insect is more efficient, but we have
seen that even the principle of this method lias been contested, and that
its application presents difficulties. The graphic method remains to be
considered. This method consists in making the wings themselves
record the strokes which they execute. When an insect is held in
captivity by force which it cannot overcome, after trial it ceases
a useless resistance ; it resigns itself and abstains from all efforts to
escape, its wings remain immovable, and in this way the observer who
hopes to study their motions finds himself disappointed. But there are
different methods of awakening the insect to its original activity ; it
is sometimes sufficient to pinch the antennae lightly ; this irritation of a
very sensitive organ succeeds with the Macrogtossa. Among the wasps
the end may be attained by titillating the feet, or by holding them all
together with a pair of forceps, and then releasing them suddenly, except
one, by which the animal is held. The captive supposes that it is at
liberty, and makes an effort at flight, which lasts about thirty seconds,
or long enough to be observed. There is, however, another difficulty.
The captive insect, when willing, cannot fly like an insect at liberty,
because the external conditions are not the same. It experiences a
greater resistance in proportion to the traction which it exerts upon the
bond which holds it ; to a free insect the relation is such as a boat held
by an obstruction bears to one sailing freely, or as a horse which drags
a load to one relieved from harness. This resistance modifies its
behaviour considerably, and obliges us to distinguish between the two
different conditions of free flight and flight in captivity. It is indispens¬
able to establish these distinctions, in order to appreciate at their true
value the results to which we are conducted by the graphic as well as
the other methods which we may employ.

The apparatus on which the wings record their motions is the
ordinary registering apparatus, consisting of a metal cylinder, covered
with smoked paper, to which a uniform rate of motion is imparted by
clockwork. Let as suppose that, instead of the motions of the wings,

A EROW AjmCAL SOCIETY

we would simply register the oscillations of a vibrating-rod. For this
purpose the extremity of the rod is furnished with a little style, which
touches the blackened paper with its point, and, as the different parts
of the movable cylinder pass successively before the point, the soot is
detached from the places which it touches, and a trace produced. If
the rod is not in vibration, it makes a long white rectilinear trace
without sinuosities, a straight line which, rolled upon the cylinder,
constitutes a circumference. If it is in vibratory motion, its trajectory
will be a curved line, of which the sinuosities indicate all the
circumstances of the motion, its phases of elevation, its depressions —
in a word, all its movements — and consequently all the oscillations
which the vibrating rod executes in space will be faithfully reproduced
on the paper. If we would ascertain the frequency of the oscillations,
it is sufficient to know the rate at which the cylinder revolves.
Ordinarily a tuning-fork is employed, of which the number of
vibrations is previously known, as, for example, one hundred vibrations
per second. This is made to write its vibrations upon the registering
cylinder below the line traced by the vibrating rod, of which the number
of vibrations are desired. The comparison of the two tracings shows at
once the number of the motions of the tuning-fork back and forth, that
is to say how many hundredths of a second correspond to one oscillation
of the rod ; the number of motions of the vibrating body during a
given time is thus known with great exactness.

It is not, however, as easy to obtain the tracing from the wing of
an insect as from a vibrating rod, and this for several reasons. In the
first place, it is very difficult to fix at the extremity of the wing a
writing style ; however light it may be, the rapidity of the motion to
which it is submitted is sufficient in most cases to throw it off. If,
however, after many trials and much precaution we are able to retain it
in its place, a permanent cause of perturbation still exists from its very
presence. Under the influence of this incumbrance the extent and
frequency of the strokes of the wing are evidently diminished. It is
easy to convince ourselves of this, by taking a Macroglossa and fixing it
in the manner which we have previously described, that is, immovably
between two strips of cork, by means of a pin. Looking down upon it,
we perceive the extreme limits traversed by the wing above and below,
which we have called the dead-points. If some substance is applied to
the surface of the wing, we see by the effect of this burden, in diminish¬
ing the play of the organ, the two limits of oscillation approach one
another, and the extreme upper position, which just now was almost
vertical, inclines towards the horizontal. We may finally remark that
it is only at the cost of considerable chafing against the surface of the
moving cylinder that we can obtain a complete tracing of the movement
of the wing. The wing cannot touch the cylinder, except during a very
short instant of its stroke ; that is, the instant when the wing reaches
precisely the distance from the body of the animal to the cylindrical
surface. The spherical figure which the margin of the wing describes
in space, cannot have more than one point in common with the blackened
cylinder. We can therefore only obtain, as the whole impression, a
series of points at more or less regular intervals ; and, if a more

OF GREAT BRITAIN.

prolonged contact is desired, it can only be by curving the wing and
folding it upon itself, and consequently the natural curve which the
organisation of the insect obliges it to traverse will be falsified and
altered. In any case the friction against the blackened surface will
retard the motion, and although the retardation which it causes may be
neglected when it is opposed to bodies of large size, such as a tuning-
fork or a vibrating-rod, it cannot be when the vibrating object is the
delicate membrane which constitutes the wing of an insect. Again, the
friction, although exceedingly small, is found fully comparable with the
forces which come in play in the motion of the wing, and its intervention
notably alters the action of the latter. Experiment has confirmed these
views. In one case an insect executing the motions of flight, and
rubbing its wings somewhat roughly against the paper, furnished 240
movements per second ; by diminishing more and more the contact of
the wing with the cylinder, there have been obtained 282, 305, and 321.
If, therefore, we would have a faithful representation, it is necessary to
renounce the idea of obtaining those beautiful, regular, and continuous
lines which are produced by the tuning-fork or vibrating-rod, and content
ourselves with interrupted lines, half-strokes, represented by fragments,
or even only isolated dots, the periodical return in these incomplete
markings of definite forms permits us to infer the repetition of similar
oscillations, and hence to determine their frequency. The operation is as
follows : with a delicate pair of forceps we hold the insect by the lower
portion of its abdomen, in such a position that one of its wings at each
movement shall lightly touch the blackened paper. Each of these
touches takes off a portion of the soot which covers the paper, and, as
the cylinder turns, new points incessantly present themselves to the
contact of the wing. A figure is thus obtained formed of a series of
points or short strokes of perfect regularity if the insect has been
maintained in a fixed position.

We have obtained a large number of these tracings in which the
wing has only touched the surface of the registering cylinder, and has
left only a point as a mark in each of its vibrations. I exhibit a number
of these, and trust as soon as the return of Spring permits us to
procure insects to show you the experiments by which these tracings have
been produced. Those which you are now examining have enabled me
to determine the frequency of the strokes of the wings of the following
insects : —

Strokes
per Second.

Common fly .. ... ... ... 330

Humble-bee ... ... ... ... 240

Honey-bee ... ... .. ... 190

Wasp ... ... ... ... ... 110

Sphinx moth ( M acroglog&a ) ... ... 72

Dragon fly ( Libellula ) ... ... ... 28

Cabbage butterfly ... ... ... 9

Certain authors have estimated this number of vibrations by the
acoustic method, but there is a notable discrepancy between the above
figures and those which they have deduced from the pitch of the sound
that these insects produce in flying. In the case of the common fly,

AERONAUTICAL SOCIETY

T. Lacordaire has computed the number of the vibrations of its wings
at 600 per second, that is to say, twice as many as our figures exhibit.
Has there not been a misunderstanding here, as is frequently the case, in
the use of the word “ vibration ? ” Some persons wrongly consider the
raising and depressing of the wing as two vibrations, and reserve the
term of “simple vibrations” for one or the other of these isolated
motions. On the contrary, if we follow the usage most generally
adopted, the two motions together, by which the body is again in its
original position, should be considered as a single vibration.

The previous observations which we have made on free flight, and
on flight under restraint, somewhat curtail the range which we are
tempted to accord to these numbers. The animal, according as it
desires to move with a greater or less rapidity, can change, at will, not
only the extent of its wing-strokes, but also, to a certain extent, their
frequency. Fatigue may exercise an analagous influence to that of the
will ; after very rapid motions, the exhausted animal diminishes the
number of its strokes, which sometimes falls to a fourth or a fifth of its
normal value. It continues to relax them more and more until a period
of repose and reparation permits it to resume its usual flight ; neverthe¬
less, the examination of these numbers suggests some general
considerations. We have reason to think that each of the muscular
contractions which determine the drawing down of the wind is the
result of a single impulse ( Zuckung of the Germans), although in man
contraction is due to successive impulses, which are merged in one
another when they are produced more frequently than 30 times in a
second. Among insects the limit of fusion of impulses is infinitely more
remote, and ends with leaving the wing immovable, in a sort of
permanent tetanic contraction. It is easy to assure ourselves of this
by means of living insects, or better, by means of the artificial insect
which I have constructed. When the impulses become too rapid, their
extent diminishes ; at this moment they no longer serve for the
propulsion of the animal, whose wings appear quite immovable or
merely agitated by a fight tremor. Nevertheless, the number of
muscular waves which the fibres of insects will admit without inter¬
mingling, a number which in the fly amounts to 300 per second, forms a
physiological fact very interesting to note. Among other animals the
limit is not so remote ; among birds fusion is produced after 75 impulses ;
among mammals after 30, and among reptifia after only 4. These
differences correspond, in virtue of the relations which I have long since
explained to you, to analagous differences in the rapidity with which the
elementary impulse traverses the muscular fibre of these different
animals. The muscular fibre of the insect will then be characterised,
physiologically, by the property which it possesses of furnishing a
considerable number of distinct impulses, as well as it is anatomically
characterized by its relative size and its striation.

The graphic process which enables us to judge of the frequency of
the strokes, also permits us to show the perfect synchronism of the play
of the wings. For this purpose it is necessary to choose an insect of
which the amplitude of the wing-vibrations is large, so that in their
moment of greatest elevation they may nearly meet above the dorsal
region of the animal. If the insect is placed near enough to the regis-

OF GREAT BRITAIN.

tering cylinder, the dorsal region turned toward the blackened surface,
it is clear that at the moment when the wings approach each other they
will leave their traces on the paper, thus describing a series of loops and
curves, of which the perfect correspondence proves the synchronism of
the motions from which they originate.

Fig. 3.

Simultaneous tracings of the wings of ,a wasp in short flight. The perfect
synchronism of the two wings will he observed.

Furthermore, we can convince ourselves that a sort of necessary
connection exists between the motions of the two wings. If we throw
an insect violently upon the ground, so that it is stunned and can no
longer execute voluntary . motions, we observe that, by producing
motions in one of the wings, the other follows, to a certain extent, the
injuries inflicted on its fellow. If one of the wings of an insect is
depressed, the other also bends down ; if one be raised, the other elevates
itself. Certain species, especially the wasp, lend themselves very readily
to this experiment. According to Chabrier, the author of an extensive
work on the mechanism of the flight of insects, synchronism cannot
fail to exist. This author considers the depression of the wing as the
only effective portion of the stroke ; its elevation is a passive
phenomenon due to the action of physical forces. In fact, after the
depression each dorsal arc of the thorax is deflected like a bent bow, and
when the muscular contraction ceases the bow springs back in virtue of
its elasticity, and the wing is raised. Now, if the pressure did not act
simultaneously on the two extremities of the bow, it could not be flexed
as it is, and the mechanism, which we suppose, would be impossible.
The reality of this synchronism is, then, a strong proof in favour of
this manner of understanding the motion of the wing.

After having determined, in a general manner, the frequency of the
vibrations of the wing,, we seek to know the variation produced in the
number of these vibrations by agents capable of influencing the activity
of the animal. In the first rank of such agents must be placed heat
and cold. We know that warm dry weather is essential to insects,
especially coleoptera, to enable them to fly well ; special observation
has confirmed this fact. We are able to state that, within certain
limits, the frequency of the strokes is augmented with an increase of
the temperature, and that they become slower under a gradual increase
of cold.

Form of the Motions of the Wings.

After having studied the frequency of the vibrations of the wings,
it is necessary to study their form. For the end which we desire to
obtain — that is, to arrive at a theory of the flight of insects — the most
important element to comprehend is that which we now proceed to
investigate, namely, the form of the trajectory which the wing
describes in space, instead of the rapidity with which this trajectory

AERONAUTICAL SOCIETY

is described. In order to arrive at this determination we shall have
recourse to two processes, which will reciprocally correct each other —
the optic method, and the ordinary graphic method.

Optic determination of the movements of the wi/ng.— When a brilliant
body moves with rapidity, it leaves upon the retina a kind of luminous
train, which acquaints us with the trajectory through which the body
has passed. Children sometimes amuse themselves' in producing the
most varied figures by brandishing in the air a stick having one end on
fire. It is on this principle that the apparatus, known in physics under
the name of Wheatstone's calidrophone, is founded. This is a rod,
fastened upright on a heavy foot, to which complex vibrations may be
given, and to the ends of which a brilliant metallic bead has been
affixed. If the rod is put into vibration the brilliant bead describes in
space luminous figures, which vary with the different combinations of
the vibratory motions. If a brilliant spangle can be attached to the
extremity of the wing of an insect, this spangle, traversing without
cessation the same points in space, leaves a continuous luminous figure
exempt from the imperfection which is caused by friction in the case of
the graphic cylinder. The extremity of an insect’s wing can thus be
rendered brilliant without mutilating it in any way ; it is sufficient to
place upon it a drop of varnish, to which a small piece of gold-leaf is
applied. The varnish dries so rapidly that the insect cannot throw off
this little reflector of light, and nothing more is necessary than to hold
the animal in a fixed position to observe the play of light upon the
small brilliant surface. Under these conditions the bee and the wasp
furnish a well-marked “ figure of eight.”

Fig. 4.

Aspect of a was]), the extremity of whose primary wings has been gilded.
The animal is supposed to be placed in a ray of light.

OF GREAT BRITAIN.

The figures of eight are more or less widened or compressed,
according to circumstances. Sometimes the point of the wing seems to
move almost in one plane. In the dragon-fly ( Libelluln) a figure of
eight is also observed, but much more elongated ; the loops are narrow
and laterally compressed. With the Macroylossa yalium it sometimes
seems as if the preceding form had disappeared, and is replaced by a
sort of ellipse. However, in examining it closely, it is soon perceived
that this ellipse is surmounted by a little loop, very slightly developed
relatively to the curve which supports it. It seems that one of the loops
is enlarged at the expense of the other, but this last has not entirely
disappeared, and the vestige what remains testifies to the persistence of
the figure of eight which is encountered in most other cases, and which
may serve as the general type.

Changes of the plane of the winy.— The luminous figure which the
gilded wing of an insect gives in its motions also shows that, during
the alternate motions of flight, the plane of the wing changes its
position in relation to the axis of the body of the insect. During the
period of elevation the upper face of the wing is directed backward,
while it turns a little forward during its descent. In fact, if we gild a
large extent of the upper face of the wing of a wasp, taking care that
the gilding shall be limited to this face, it is seen that the insect, placed
in a ray of light, gives the figure of eight with a very unequal intensity
on the two sides of the image, as is seen in the preceding figure. It is
evident that the cause of this phenomenon is found in a change of the
plane of the wing, a change in consequence of which the angle of
incidence of the solar rays, while favourable during the ascent of the
wing, is unfavourable during the descent. If the animal is turned so
that the luminous figure is observed inversely, the figure of eight
presents, in an inverse position, the striking inequality of its two
halves, catching the light in a portion which was just before without it,
and losing it where it had previously shone. We further find, in the
employment of the graphic method, new proofs of the changes of plane
in the wings of insects during flight. This change of plane is of great
importance, for in this rests, as we shall see, the immediate cause of the
propulsion of the body of the animal by the application of the motive
force.

Method of contact. — Does the extremity of the wing really describe
this double loop which we perceive, or is this form the result of an
optical illusion — a play of flight ? Though such an objection is hardly
probable, it is necessary to refute it. To assure myself more entirely of
the reality of the displacement of the wing than the optic method
rendered perceptible, I have introduced, while the w'ing was in motion,
the extremity of a little bodkin into the interior of the loops of the
figure of eight, and J have established that in the interior of these
curves free spaces really exist of a funnel shape, in which the
bodkin penetrated without encountering the wing, while if I attempted
to touch the intersection where the lines cross, the wing immediately
struck against the bodkin, and flight was interrupted. Still greater
precision can be brought to bear on the appreciation of these motions,
and, knowing that the wing describes a double loop, it may also be

-iEROK ATTIC AL SOCIETY

known in what manner it transverses the branches. It is sufficient to
bring near to the wing in motion a leaf of paper blackened on both
Rides ; the wing, in pursuing its course, strikes against one of the sides
of the paper, and the trace which it leaves testifies to the manner in
which the motion is accomplished.

Graphic method. — This method is not applicable to our problem
without important modifications. We have just seen that it is difficult to
obtain tracings of any extent, because the wing cannot remain long in
contact with the blackened cylinder, which it leaves and approaches
successively. Under these special conditions it is necessary to have
recourse to an artifice, and since it is impossible to obtain a satisfactory
trace at a single stroke, we rnould try to divide the difficulty and
separate the operation into several periods. The preceding experiments
simplify the interpretation of the tracings very much, and we can
reconstruct the, figures which the optic method has indicated from the
slender elements which they afford. I have considered in the complete
course of the wing of an insect, such as is represented in Fig. 4, three
distinct zones, of which I have obtained the tracings separately ; an
inferior zone, corresponding to the lower portion of the figure of eight ;
a median zone ; and a superior zone corresponding to the middle and
upper parts of this figure. Bringing together the tracings obtained in
these three zones, I have been able to reconstruct the entire curve. In
registering the tracings of the median zone, figures much resembling
each other are obtained, presenting the two crossed lines shown in Fig. 5.

Fig. 5.

Trace of the median course of the wing of the Macroylossa galium (Bedstraw

sp’nynx moth).

The multiple tracings of the figure are formed by the fringed
extremity of the wing, which presents many small points. The upper
portion is in the form of a loop, as well as the part which corresponds to
the lower course of the wing, and these three parts successively obtained
give, when united together, the complete representation of a figure of
eight, such as is obtained in acoustics in registering by Koenig’s method
the vibrations of a Wheatstone’s octave rod ; that is, a rod which
vibrates twice transversely for each longitudinal vibration. The slower
motion of the cylinder produces the condensation of the end of the
tracing.

OP GREAT BRITAIN.

Pig. 6.

Trace of a Wheatstone’s octave rod.

The experiments can also be varied by obtaining, not the tracing of
the point of the wing, but that of the anterior border of this membrane
striking laterally against the cylinder. It is clear that in describing the
upper loop, this edge will approach the cylinder, then deviating, in a
similar manner it will describe the lower loop, so that in its complete
course it will rub twice against the blackened surface, and leave two
white traces separated by an interval. This is observed in Tig. 7.

9 ' v

i . ,

- . > ■ - v - t

v v ; P - ' : ; ‘

. if

f ' ' ' ' | , ) j | ! 1 >

This figure shows from the tracing of the wing of a wasp the upper
loop and the whole extent of one of the branches of the figure of eight.
The median portion of this branch is only dotted on account of the
feeble friction of the wing. We may, therefore, be permitted to con¬
clude that if the trace of an insect’s wing could be obtained entire at
one operation, the same figure would be presented which we have seen
described in space by the gilded spot on the wing of the wasp, namely,
a figure of eight, which our ingenious acoustician, Kcenig, was the first
to obtain with a spiral Wheatstone’s rod, making two horizontal to one
•vertical oscillation.

It now appears to me sufficiently established tnat in the more
extended motions of flight the wings of insects describe a figure of eight
in space. Furthermore, that the luminous figure which a speck of gold
on a wing presents in its motions, has shown us that the periods of
ascent and descent of the wing are accompanied by a change of plane
in that organ. It is this fact which will shortly enable us to explain
the mechanism of flight in insects.

AERONAUTICAL SOCIETY

Mechanism of the Flight of Insects — How they Propel

Themselves.

The preceding lessons have been devoted to the study of the
frequency and the form of the strokes of the wings of insects. You
have seen that the frequency varied in different species, and in passing
from the butterfly, for example, to the house fly, or the gnat, the
variations may be considerable. The flight of the butterfly is slow, the
strokes of its wings succeed each other at considerable intervals,
propelling it by bounds and jerks, and producing ap irregular and
capricious flight. The gnat darts with rapidity straight at its object,
emitting along its path a clear, sharp, strident sound. Between these
two extremes we find all intermediate stages. Furthermore, the same
insect, under different conditions, varies the rapidity of its motions
within extensive limits ; when free from all restraint its movements are
rapid and precipitous, but when captured they are immediately relaxed,
and although the frequency of the movements of the wing varies, the
form of the motion does not change. It is in all cases the same, always
a double loop, a figure of eight. Whether this figure be more or less
apparent, whether its branches be more or less equal, matters little ; it
exists, and an attentive examination does not fail to reveal it.

Before drawing from this fact the conclusions which it warrants ;
before extracting from it the solution of the problem with which we
are occupied — that is to say, the mechanism of flight— let us rapidly
review the history of the question, and see how far previous authors
have advanced in its solution. Without going further back, we find in
the work of Borelli a chapter devoted to this subject, in which lie
considers the force which the bird or insect must employ to sustain or
move itself in space. He estimates that this force is enormous ; that it
is, in the case of the bird, more than ten thousand times greater than
the weight of its body. We still find this exaggeration in recent works.
The academician, Navier, falls into an analogous error, and after him
M. Babinet accords, in his turn, a power to the inhabitants of the air
far superior to that with which they are gifted by nature. However,
by the side of these errors we find a great number of correct ideas,
since confirmed by observation. Borelli knew that the principal motion
of the wings was an elevation and depression, executed in a vertical
plane, and he asked himself how it was possible that this motion, which,
it seemed to him, could only serve to elevate the animal or to depress it,
should nevertheless contribute to onward motion. For this, it was
necessary that the vertical force should be changed into a horizontal
force. Example" of t’ is transformation are frequent. If a wind
blowing horizontally strikes against a flat board inclined forward at an
angle of, say, forty-five degrees with the horizon, the action of the wind
will tend to throw it backward and upward ; or, if the board is moving
forward with a momentum, it will tend to elevate it. We have here an
illustration of a well-known principle of mechanics — the resolution of a
single force by an inclined plane into two forces — which gives in part an
explanation of the flight of insects and of water birds. But insects
have four wings instead of two. Is the office of these four organs the

OF GREAT BRITAIN.

same ; and if not, in what do they differ ? Borelli does not treat of this
question. It is discussed, however, in a particular case, by an
anonymous author, who has left us an interesting manuscript on the
habits of bees. This work, intended to complete and to correct the
work of Reaumur, came from the Condamine Library, and belongs to
M. Hamet. The author has observed bees at the moment when they
hum at the mouth of the hive, trying to enter it and deposit their
treasure. In examining the play of light on their trembling wings, he
thinks that he saw the upper pair alone alternately raised and depressed,
while the lower pair were animated only with a. feeble horizontal
motion. Here the question seems to have been abandoned, although
the interest with which it is now regarded is far from inconsiderable.
Beside the interest which it offers from the purely scientific point of
view, in the mechanism of a function #as widely employed as aerial
locomotion, still another interest is attached to this study. The insect
and the bird realize one of the oldest and most unsuccessful aspirations
of the ambition of man. A 11 space belongs to them ; they go and come
in the aerial ocean, while he is chained by his weight to the earth. Man
has sought by various methods to escape from this confinement. The
knowledge of the processes by which Nature attains the end to which
he aspires, would perhaps have spared him many fruitless attempts and
loss of much time and great waste of invention. In 1823 a work
appeared in which this question of aerial locomotion is treated ex
professo, and no longer in an incidental manner. The author, the
Chevalier de Chabrier, studied the conditions of mobility of the wing,
and arrived at the solution of an important question : how muscular
action is transmitted to this movable organ. Is it directly, or by some
intervention 1 The muscle, responds Chabrier, is not directly attached
to the wing ; it acts upon the arch of the hack. When it contracts, the
curvature of this arch is augmented ; when it relaxes, the back returns
to its original curve, like an unbent bow. In the motion of the wing,
therefore, there is only one active period, the moment of depression ;
the period of elevation is passive. Elasticity, therefore, plays an
important part in this function. Here, as in all mechanical organs, it
absorbs and then gives out power ; it regulates speed and produces
continuity of motion.

But Chabrier was soon carried away by an exaggeration similar to
that of Borelli and of Navier, though in a contrary direction.
According to him, an insect needed an insignificant force for its
propulsion in space. No effort was necessary to sustain it in the
atmosphere ; the animal floated there like an inflated balloon. In order
to fly it filled its multitude of respiratory canals with air, and this,
becoming heated, raised the animal as it elevates a hot-air balloon. It
is not necessary to say that this conception of an aerostatic insect is an
error. Without doubt an insect, before attempting a flight, lays in a
quantity of air by a sudden respiration, but this provision of air
contributes only an insignificant part toward the end which Chabrier
assigned it.

The greater portion serves to prepare the organs of flight for the
operation of their function. Jurine, of Geneva, in particular has

AKRON ATTIC AX. SOCIETY

shown that the nervures of the wing membranes are small tubes which
only acquire the rigidity and extension necessary to flight by inflation
with air. We must refer to another contemporary, Strauss Durckeim,
to find the elements of the theory to which my observations have
conducted me. In his book on the Theology of Nature, a vast chaos of
ingenious ideas, in which some profound, among many puerile, thoughts
are to be found, there are many facts essential to the solution of our
problem. Strauss Durckeim has conceived the ideal type of the insect-
wing, the diagrammatic wing ; that is to say, has reduced the organ to
its essential parts. It consists of a rigid nervation or frame-work in
front, a flexible web behind ; this is all the apparatus. An apparatus
thus constituted possesses the essential requisites for flight ; otherwise
constituted it will not serve this purpose, as is the case with the false-
wing of the Phryganidce, which has its principal nervation behind. It
is enough that such a structure should be made to rise and fall
successively : the forward border being rigid and the other flexible, it
naturally disposes itself in an inclined position, receiving the reaction of
the air obliquely, and thus transforms a part of the vertical impulse into
a horizontal force. The two parts of the wing above mentioned are
both indispensable in the same degree their respective offices complement
each other in producing a single result. Ingenious experiments, due to
M. Girard, throw light upon these facts. Destroy the anterior
nervation, without removing the thin membrane, and the insect cannot
fly ; destroy the flexibility of the membrane by covering it with gum,
and flight also becomes impossible. Here we cannot urge the objection
that the superincumbent matter interferes by its weight like a burden
which weighs down the animal ; for, following out the experiment, we
see that as soon as the coating becomes dry, small fissures are produced,
flexibility reappears, and with it the possibility of flight returns.
These observations assist us in comprehending the part which the
anterior portion of the wings of the Phryganidce play ; which constitute
the analogue of the stiff nervure, while the hinder wings represent
the flexible membrane. The two wings of an insect thus complement
each other.

I shall not further prolong this retrospect. I have limited it to the
essential ideas entertained by our predecessors, and to those which will
serve us in the future. The preceding experiments, joined to those
which you have seen performed under your own eyes, seem to me to
establish the following facts, namely : the motions executed by an
insect during flight are- limited to an elevation and a depression of the
wings. It is true that other motions take place in the wings of insects.
They are seen to move backward, and in repose to extend parallel to the
axis of the body. We also see insects moving their wings backward and
forward in preparation for flight. But these motions are not directly
connected with aerial locomotion. The dragon-fly ( Libelhda ), which
propels itself so rapidly, exhibits none of these lateral movements ; its
wings move exclusively in a vertical plane as if they turned on a hinge.
But we have seen, in the optic method, that the course of the wing in
space can be followed by gilding its extremity, and placing it in a ray of
sunlight. Now this arrangement furnishes us with a figure of eight,

OR GREAT BRITAIN.

and we further know that during each complete vibration the wing
changes its inclination twice. These movements are not controlled
directly by the muscles. They are the mechanical effects of the
resistance of the air acting alternately on the upper and lower surfaces
of the wing in its alternate movements. When the wing leaves the
upper limit of its position it inclines neither to one side nor to the
other, its plane being parallel to the length of the animal. But when
the impulse of the air is exercised, or as soon as the wing begins to be
depressed, the rigid portion, the anterior nervation resists flexure while
the flexible membrane which follows it gives way ; drawn down by the
nervation which lowers it, elevated by the air which uplifts it, this
membrane takes an intermediate position ; it inclines about 45 degrees,
more or less, according to circumstances. The wing continues its
downward motion thus inclined toward the horizon. Thus the reaction
of the air, which combines its effect and acts perpendicularly upon the
surface which it strikes, can be decomposed into two forces, a vertical
and a horizontal force ; one serving to elevate and the second to propel
the animal. After this first period the wing membrane will have arrived
at the end of its course ; the direction of its motion is changed, its action
is reversed. A moment of repose, infinitely short, separates these two
phases during which the wing resumes its normal position parallel to
the axis of the body. The nervure draws it up again, the air resists as
before, and from this conflict results a position between the horizontal
and the vertical — an inclination of 45 degrees. This second period
contributes as did the first, to locomotion. How remarkable is the
simplicity of apparatus by which the desired end is attained !

The horizontal force which is generated by the inclination of the
plane of the wing is transmitted to the body of the animal and helps to
push it forward. But as the body of the insect does not instantaneously
take up the motion which is imparted to it, a part of this force is
expended in curving the nervure of the wing which, at the same time
that it is lowered, is pushed forward. Here is an artifical wing of large
size constructed in accordance with the type which we have described ;
an anterior nervation represented by a stiff rod, with a membrane behind
formed of paper pasted upon its edge. Try to strike down an object
immediately before you, and you will not succeed. If you strike at an
object before you with a downward blow the wing will be resisted by
the air, and it will deviate greatly from the point at which you are
aiming. From this deviating motion of the wing from the change of
plane which it effects, the looped figure which it describes evidently
results. It is the combination of these motions which generates the
figure of eight previously described. We can now safely say that the
two experimental facts are now interpreted by our theory.

A very slight difference has been observed between the two sides of
the wing in certain insects ; the lower surface is less polished than the
upper ; it is furnished with rugosities, hairs, or points, which according
to Ohabrier, give more hold on the air and reduce the loss of force by
sliding. This disposition may contribute to insure the predominance of
the useful effect of the lowering over the elevating motion. Further¬
more, this predominance of the depressing action of the wing does not
exist in all insects. These find that force as well in the period of

AERONAUTICAL SOCIETY

elevation of the wing as in the period of its depression, turning almost
horizontally the plane in which their wings move. The numerous
varieties which the mechanism of flight presents among the species of
insects which we have observed will be studied later ; they do not
conflict with the fundamental principles which 1 have just announced.

The mechanical conditions which we have just' passed in review
I have realized in a theoretical apparatus, from which I have obtained
the same results as afforded by living insects. This artificial insect is
represented by Fig. 8.

An air-pump, moved by a rotary apparatus, alternately compresses
and relaxes the air in a tube which traverses the central pivot of the
apparatus, where a sort of mercurial gasometer hermetically seals it
while permitting the free rotation of the arms. The horizontal branch
is hollow, and conducts the air into the apparatus, which is closed by a
hollow metallic drum, of which the two circular faces are closed by two
sheets of rubber. By the play of the air-pump these two sheets are
inflated or contracted both together. They communicate the rapid
motions of elevation or depression to the wings by two angular levers.
The wings presenting, like those of an insect, conditions of unequal
flexibility, decompose the resistance of the air, and impart to the apparatus
a rapid rotary motion around the central pivot.

Imagine two artificial wings, as nearly alike as possible, both inserted
on one of these little drums, which I have frequently described. They
receive through this drum absolutely synchronous motions of elevation
and depression. This apparatus is fixed at the extremity of an arm
balanced by a counterpoise, and turning upon a pivot. This arm is
hollow, furnishing a canal by which the effect of inflation can be trans¬
mitted to the movable drum of the wings. We may consider the drum
as representing the body of the insect, and nothing prevents us from
really giving it the shape of this animal. The rigid nervures, furnished
with flexible membranes disposed to the right and left, will be the two
wings, and the animal, instead of being free, will be fixed at the extremity
of a movable rod ; there is, therefore, only a single motion possible,
which is that of turning around the pivot, carrying the attached rod with
it. In effect, if I put the air-pump in motion, the artificial insect moves,
flaps its wings, and really flies. At each stroke there is a change of
plane of the alar membrane ; at each stroke the point of the wing
describes a figure of eight ; and in a general way this theoretical animal,
this artificial insect, reproduces all the particulars which the observation
of real insects has revealed to us.

This apparatus affords many other advantages besides those of
verifying theoretic ideas. It enables us to make new experiments, to
which living beings will not lend themselves. We can change one of the
conditions, for example, the form of the wings, their extent, or the
rapidity of the stroke, or any other of the circumstances, while all the
others remain constant ; we may thus discover the influence which each
of them singly may have on the mechanism of flight. It is by such
experiments that we can assure ourselves of the following fact. In the
course traversed by the wing there is only one region useful in the
propulsion of the insect ; that is the median region. In the two extreme
portions the wing has not experienced that change of plane which renders

Representing the artificial insect or scheme of the flight of insects.

OP GREAT BRITAIN

40 AERONAUTICAL SOCIETY

its action effective. Thus we see if we diminish the extent of the motions
of the wing, the tractile power produced by the apparatus diminishes
considerably, and finally ceases altogether. If the membrane of the
wing is too broad, another phenomenon results. The hinder edge of the
wing remains almost immovable in space, especially during motions of
small amplitude ; the nervure only is animated with rapid motion. The
air, therefore, is struck by planes inclined inversely to those which act
upon it in normal flight, so that the apparatus retrogrades and turns
around its pivot in a direction contrary to its usual motion.

Experimental flight also shows the adaptation of certain forms of
wings to obtain the most rapid translation of motive force. These are
precisely the forms which we find in nature. The nervure of insects
does not cariy the wing membrane back to its point of insertion. Those
parts near the articulation have little vitality ; they contribute very little
toward a useful result, embarassing the neighbouring parts, without
compensation of any kind. The membrane should not exist except when
vitality itself exists in a corresponding degree. Finally, the extent which
the alar membrane should have, to best utilize the disposable force, can
be determined experimentally. M. de Lucy has compared, in the case
of a certain number of animals, the surfaces of the wings to the total
weight of the body. He finds an extent of 30 square millimetres in a
gnat weighing 3 milligrammes; 1,663 square millimetres in a butterfly
weighing 20 centigrammes ; 750 square centimetres in a pigeon

weighing 290 grammes; 4,506 square centimetres in a stork weighing
2,265 grammes ; 8,543 square centimetres in an Australian crane,
weighing 9,500 grammes. But to facilitate the comparison it is necessary
to reduce these figures to a common measure ; and in spite of the
barbarous phrases to which they lead us, we obtain :

Square metres.

The kilogramme of the gnat represents ... ... 10'0

The kilogramme of the butterfly represents .. . ... 8 0

The kilogramme of the pigeon repi’esents ... ... 2586

The kilogramme of the stork represents ... ... 1 '988

The kilogramme of the Australian crane represents... 0'899

The extent of the wings, therefore, is not proportionate to the size
of the animal. A wing being given, a maximum rapidity of stroke
corresponds to it. To augment the rapidity of the stroke, in hope of
indefinitely accelerating the rate of flight, would be illusory ; it is possible
to accelerate it up to a certain point, but beyond this maximum limit
additions become useless. Increasing progressively the action of the
air-pump, the strokes of the wings are more rapid, and at first the
rapidity of flight will be augmented. Continue the increase, and the
rate of flight diminishes. The amplitude of the motion also experiences
a considerable reduction, so that at the limit the wings appear motionless,
or animated only by a slight quivering. Passing this extreme limit, the
apparatus retrogrades. A given wing then corresponds to a fixed rate of
progressive strokes ; for, by the effect of inertia, the frequency of the
strokes is increased only at the expense of their extent, and, when the
extent diminished, the propelling force diminishes with it. I leave to
yourselves the task of explaining these facts, which are the simple

OP GREAT BRITAIN

consequences of the principles I have previously explained. I also leave
to you the comparison of the mode of progression of insects with the
other modes which are seen in other animals or in various mechanical
contrivances. You will discover almost everywhere the mechanism of
the revolution of forces on the principle of the inclined plane. You will
find it in the motion of the tail of a fish, the principal organ of its
locomotion ; in the sculling motion of a waterman’s oar, and even in the
screw of a steam propeller.

Flight of Birds.

By the simple inspection of a bird’s wing it is easily seen that its
mechanism for flight is not the same as that of an insect. Let the
manner in which the feathers of birds are laid, one over another, be
observed, and it will be evident that the air resists the motion of the
wing only from below, so that in an inverse direction it finds an easy
passage between the long beards of the feathers, which, in this motion,
are no longer pressed together. This well-known arrangement, the effect
of which Prechit* has clearly pointed out, has led to the belief that to
sustain the bird against gravitation the wing needs only to oscillate in a
vertical plane, in consequence of the predominance of the resistance of
the air acting from below over that acting conversely.

******

All thin curved bodies tend to slide upon the air in the direction of
the radius of their special curve. If we bend thp anterior or posterior
edge of our little apparatus at a certain point in its oblique course, we
shall see it rise, notwithstanding the force of gravity, though its potion
soon ceases. What has happened in this case ?

Fig. 18.

^V7.

Representing to the left Pline’s apparatus placed in equilibrium by means of
two equal balls at the extremities of the rod which lies at the bottom of the hngle
of the bent paper. This, as is indicated by the lower representations of tfie rod,
falls vertically. To the right the same apparatus, with only a single tell, is
represented, "it descends in a parabolic curve, represented by the dotted line.

* U ntersuchungen tlber den Plug der Vogel. 8vo. Vienna, l$f6.

AERONAUTICAL SOCIETY

When there has been but little rapidity in the fall of the object, the
curve of its surface remains motionless, because the air offers resistance
only in proportion to the rapidity with which they move. Therefore,
when this rapidity has been sufficiently great a steering effect is produced,
which elevates the anterior extremity of the object and imparts an
ascending motion to it. But very soon the weight, which was the motive

Fig. 14.

line indicates.

power of the apparatus, becomes a retarding force, and in proportion as
the object ascends its motion becomes slower, and finally ceases. After
this, retrogradation begins, to be followed by another rise, and so on,
until by successive oscillations the apparatus finally reaches the earth.
I may add that if a slight concavity is given to the object below, the
reverse takes place, and we see at a certain moment the trajectory
sharply deflected downward, and the object strikes the earth with great
violence. In the second case, at the moment when the steering effect is
produced, the weight is in a favourable position for a precipitate descent,
and opposed to the ascending reaction.

I emphasize these effects because they are frequently produced in
the flight of birds. The old treatises on falconry describe the interesting
evolutions of the birds employed in hunting. Without going back
further, we find in Huber (octavo, published at Geneva in 1784) a des¬
cription of the curvilinear movements of the falcon, to which they gave
the name of passades, and which consisted in an oblique descent of the
bird, followed by a rise in its course. “The bird,” says Huber, “when
about to strike the earth, carried away by its own rapidity, would be
dashed to pieces if it did not call into action a certain faculty, which it
possesses, stronger than its descending motion, to rise even high enough
to make a second swoop. This motion is sufficient, not only to arrest
its descent, but even to carry it without effort as high as the elevation
from which it came.”

OF GREAT BRITAIN.

Fig. 15.

The posterior corners of the paper have been bent downward. After passing
through a parabolic curve the object takes a very rapid descending course.

There is certainly exaggeration in the statement that the bird
remounts as high as the elevation from which it descended without
further effort. The resistance of the air must overcome part of the force
acquired during the descent, and which is transformed into ascending
force. We see, however, that the phenomena above described is
confirmed by observation, and that it has been considered in some sort
as a passive act in which the bird expends no muscular power. The act
of hovering in some cases presents a great analogy with the phenomena
just described. When some birds, pigeons for instance, have used their
wings during a certain distance, the wings are seen to be perfectly quiet
during a few seconds gliding through the air, either horizontally or rising
or falling. The descending motion has the longest duration ; in fact, it
is only an extremely prolonged descent in which motion is maintained
by the force of gravity, which diminishes it in the horizontal or ascending
plane. In these latter forms the wing, more or less obliquely directed,
takes hold on the air like the toy kite, with this difference, that motion
is imparted to this by pulling the string when the air is calm, while the
bird utilizes momentum previously acquired by an oblique descent or
previous strokes of the wings.

I have already said that observers have admitted that certain birds,
which they call sailors, can sustain and direct themselves in the air by
means of the wind alone. This theory appears paradoxical. It is incom¬
prehensible that a bird, motionless in the wind, should not yield to the
resistance of the air through which it glides. If the passades or swoops
which tlie falcon executes can sometimes carry it against the wind, this
can only be a transient effect, compensated for I v being carried away by
the wind more rapidly in another moment. However, this theory has
been sustained with great talent by some observers, especially the

AERONAUTICAL SOCIETY

Count d’Estemo, the author of a remarkable memoir on the flight of
birds. “Every one,” he says, “can see some birds practising this
method of flight ; to deny it is to deny self-evident facts.” I myself
have noticed this mode of flying, but it has seemed to me that it is
executed in general under the following special conditions : Along the
cliffs of the coast of Normandy I have seen the gulls and sea-mews
performing their evolutions without moving their wings. 1 have seen
the daws and rooks flying in the same manner around old cathedrals.
But the same birds, when they left these special stations, have always
appealed to me to use the rowing method of flight ; that is to say, making
regular strokes of their wings, sometimes interrupted in the daws by
swoops of short duration. I then sought to determine the direction of
the wind, and this is what seemed to me to occur : When a bird finds
itself in the neighbourhood of a cliff, where the air is calm or agitated by
eddies in a contrary direction to the prevailing wind, it can pass
successively from the calm to the agitated air, and conversely. A sea-
mew surrendering itself to the force of the wind, receives an impulse
which carries it with a certain rapidity, and if, by simply turning, the
bird enters a region of calm air, it can utilize the impulse which the
wind has given it in returning to the height which it had left. Plunging
again into the zone of agitated air, it recommences the evolution which
I have just described, without moving its wings, except to give them
different inclinations, The daws and rooks appear to me to find the
same conditions around the cathedral towers. The authors who have
reported the most curious cases of sailing flight have observed them in
mountainous regions. It is a condor in the Cordilleras, or an eagle in
the Pyrenees. The sailing flight has often been described of certain
birds of prey, who, in the middle of a plain, rise and turn without moving
their Wings I myself have often seen harriers fly in this manner, but I
have always determined, also, that in this case the spiral which they
describe is altered by the wind, and that the birds are definitely carried
to leeward with a more or less rapid motion.

Even when reduced to these limits the influence of the wind on the
flight of birds is very difficult to explain. It is complicated by very
different conditions in which the motion acquired by the bird, opposed
from various directions by the force of the wind, gives rise to the most
varied combinations of motion. It is also known that in the upper
regions of the air various currents exist, sometimes even in a contrary
direction to those which obtain near the surface of the earth, so that the
bird, passing from one to another, finds forces which carry it in opposite
directions.*

Finally, the question of sailing flight seems to me one of the most
difficult to solve. It would be temeritouB to absolutely condemn the
opinion of observers upon such vague theories and ideas as we possess
upon the subject.

One of the most interesting points in the conformation of birds

* The late Mr. Espy suggested that the phenomenon of sailing in the flight of
birds is due to upward currents of air which take place in warm weather, or
beneath clouds, and especially up the side of a mountain against which the wind
is blowing.— J H.

OF GREAT BRITAIN.

consists in the determination of the relations of the extent of the alar
surfaces to the weight of the animal. Is there a constant relation between
the weight and these surfaces? This question has been the cause of
numerous controversies. It has been already shown that if birds of
very different kinds, yet of the same weight, be compared, the wings of
some species are found to have four or five times the extent of others.
The birds which have large wings are usually those which have been
called “ sailors,” while those which have the wing short and narrow are
generally classed as “rowers.” But if we compare two “rowing” birds
with two “sailing” birds ; if, for still closer comparison, we take them
from the same family, in older that the only differences shall be those of
form, a somewhat constant relation will be found between the weight of
the bird and the surface of its wings. But the determination of this
relation should be based upon certain considerations, which have long
escaped the attention of naturalists. Mr. de Lucy sought to measure
the surface of the wings and the weight of the body in all flying
animals. Now, to establish a common unit among animals of such
different kinds and forms, he reduced all the measures to an ideal type,
of which the weight should always be one kilogramme. Thus, after
having proved that the gnat, which weighs three milligrammes, possessed
Wings with a surface thirty millimetres square, he concluded, in the
types represented by the gnat, the kilogramme of animal was supported
by an alar surface of ten square millimetres. By making a comparative
table of the measures taken from a great number of animals of different
kinds and various forms, he arrived at the following figures : —

Species.

Weight.

Wing surface.

Surface

per kilogramme.

Gnat .

3 milligrammes...
20 centigrammes
290 grammes .

30 sq. millimetres . . .
1,663 sq. millimetres..
750 sq. centigrammes
4,506 sq. centimetres
8,543 sq. centimetres

10 sq. millimetres

81 sq. millimetres
2,586 sq. centimetres
1,998 sq. centimetres
899 sq. centimetres

Butterfly .

Pigeon .

Stork .

2,265 grammes ...
9,500 grammes ...

Australian crane

From these measurements, in spite of variations in detail, the
evident result is obtained, that animals of large size and great weight
sustain themselves with a much smaller proportional alar surface than
smaller animals. A similar result already shows that the office of the
wing in flight is not merely passive, for a sail or parachute should always
have a surface proportioned to the weight which acts upon it ; considered,
on tne contrary, from its true point of view, that is to say, as an
instrument for striking the air, the wing of the bird should, as we shall
see, present a relatively smaller surface in birds of large size and great
weight. The astonishment exhibited at the result of the determinations
marie by Mr. de Lucy disappeared when it was remembered that there
was a geometrical reason why the alar surface could not increase in
proportion to the weight of the bird. In fact, if we take two objects of
the same shape, two cubes, for example, of which one shall be twice as
large in diameter as the other, each one of the faces of the larger cube

AERONAUTICAL SOCIETY

will be four times as large as the corresponding face of the smaller, while
the weight of the greater cube will be eight times that of the lesser one.
For all similar geometrical solids, the linear dimensions having a stated
relation to each other, the surfaces are as the square and the weight as
the cube of their similar linear dimensions. Two birds of similar form,
but having, one of them, the spread of the wings from tip to tip twice as
great as in the other, will have respective wing surfaces in the proportion
of 1 : 4, and weight as 1 : 8. M. P. Demonddsir, who applied these
principles before me, thought that he had found in them a reason for the
smaller size of birds being capable of flight, while those of a larger kind,
such as ostriches and cassowaries, do not fly ; he observes that if these
birds had as large wings as the heron in proportion to their weight, they
could not fold them completely, and would drag them as long and
embarrassing appendages. These observations would be correct according
to the theory of “sailing” flight, but, in “rowing” flight, the amplitude
of the stroke of the wing, increasing in proportion to the size of the bird,
multiplies the resistance which the wing meets from the air, and the
reaction bears a similar proportion to the weight of the birds themselves.
Dr. Hureau de Villeneuve, upon the same principle, has sought to
‘determine the alar extent which would enable a bat of the same weight
as a man to fly. He found that each of its wings would be less than
three metres in length.

A remarkable work by Hastings* has appeared this year on the
relative extent of the wings and the weight of the pectoral muscles in the
different species of flying vertebrate animals. The author first shows
that among birds the existence can be established of a certain relation
between the surface of the wings and the weight of the body. But we
should be careful to compare only comparable elements ; that is to say,
the length of the wings, the square root of the alar surfaces, and the
cube roots of the weight among different birds. Let l be the length of
the wing, a its area, and w the weight of the body, we can compare
among themselves l, -j/^ \/v^

Examining different types of birds, Hastings made weights and
measurements, from which the following table is extracted : —

Species.

Weight.

Surface.

Relation
between them.

to.

a .

1 /a Vu> d- Vw

Laurus argentatus .

565'0

541

2'82

Anas nyroca .

508'0

321

2'26

Fulicaatra .

495‘0

262

2-05

Nettion crecca . . .

2756

144

184

Laus ridibundus .

197‘0

331

313

Machetes pugnax .

190'0

164

223

Rallus aquatlcus .

170'5

101

1"81

Turdus pilaris .

108'4

101

2T4

Turdus inerula .

88'8

106

231

Sturaus vulgaris .

86’4

2’09

Bom by cilia garrula .

60'0

1'69

Alauda arvensis .

82'2

2-69

Parus major . . .

145

2-29

Fringilla "spinus .

10'1

233

Parus cteruleus .

2-34

* Arohives Ne&rlandaises, t. iv. 1869.

OF GREAT BRITAIN.

The weight of the pectoral muscles is, on the contrary, in simple
proportion to the total weight of the bird, and in spite of the differences
which correspond to the different degrees of aptitude to flight with which
each species is endowed, we perceive that the proportion of the weight of
the pectoral to the total weight is about one-sixth in the greater number
of birds.

Each animal capable of sustaining itself in the air must develope a
force proportional to its own weight, and should possess an amount of
muscle proportioned to this weight ; for, as we have seen, if the chemical
action which takes place in the wings of birds be always of the same
nature, this chemical action and the power which it generates will be
proportionate to the size of the muscular masses. Now, how is it that
the wings of birds in which the surface varies as the square of the linear
dimensions suffice to move bodies of which the variation is in proportion
to the cubes of these dimensions ? Here it is necessary to bring in the
theory of power ; that i3 to say, of resistance multiplied by the square of
the distance through which it acts in a given time, admitting a uniform
rate for the downward stroke of the extremity of the wing in two
birds to be compared, and which have the proportion of 1 : 2 in their
linear dimensions. The surface of the wings of the larger bird will be,
as we have already said, four times as great as that of the smaller one ;
now, as the resistance of the air against surfaces moving at the same rate
is proportionate to their extent, if we call the resistance experienced by
the wing of the small bird r, that for the large bird will be 4r. But
these birds, in the downward stroke of their wings do not execute motions
of equal amplitude. In the large bird each point of the wing will travel
twice as far as the similar part of the smaller bird. If we call the space
traversed y, the resistance r, which the wing of the small bird encounters,
we shall have ry for the work done by the wing, and 4r 2 y or 8 ry for
the work done by the bird. We see, then, that this work increases in
the same proportion as the weight of the animals we are comparing.

Another conclusion results from the preceding considerations. If
we admit that the wing possesses the same velocity in both birds, the
duration of the stroke will increase with the space traversed by the wing ;
that is, it will be proportioned to the linear dimensions of the bird.
Observation confirms this view by showing that large birds make fewer
strokes than small ones do. We have not yet been able to determine
exactly the number of strokes of the wings of birds to ascertain if their
frequency presents an exact inverse ratio to the size of the animal, but it
is easy to see that it is in this manner that the frequency of the wing-
strokes of birds varies.

The granhic method, which is easily employed in determining the
frequency of the wing-strokes of insects, cannot be similarly employed
with birds. It is necessary to adopt some method of transmitting signals
from the flying bird to the registering apparatus. For this purpose I
have first used the electric teleyraph, which furnishes the means of solving
the following questions : — 1. What is the frequency of the strokes of the
wings of a bird ? 2. What are the relative durations of the periods of

elevation and depression of the wings ? The experiment consists in
placing at the extremity of the wing an apparatus which breaks or closes

AEBQ1T4,WICAP ^ppCftTY

an electric circuit at each ot the alternate motions, while at the further
part of the circuit is placed an electro-magnetic apparatus, which makes
a trace upon a turning cylinder. Fig. 16 shows this method of studying

Fig. 16.

Apparatus for registering the motion of the wing of a pigeon by double signals.
In one ease a small India-rubber tube transmits the record of the muscular
action ; in the other the periods of elevation and depression of the wing, with
their relative durations, are noted by ap electric signal.

Or GREAT BRITAIN.

the flight of a pigeon, together with another method of transmitting
signals. In this figure the two wires are separated from each other.

The writing style traces a crenulated line, of which the changes of
direction correspond to a change in the direction of the motion of the
wing.

In order that the flight may be as free as possible, a fine, flexible
cord, containing two wires, establishes the communication between the
bird and the writing telegraph. The two ends of the two wires are
attached to a very small light apparatus which, from the resistance of
the air, executes a kind of valvular motion. When the wing is elevated
the valve opens, the circuit is broken, and the line traced by the telegraph
rises. When the wing descends the valve closes, the circuit is also
closed, and the line is depressed.

Applied to different kinds of birds, this apparatus registers the
frequency of the strokes of the wing in each. The number of species
which I have as yet been able to study is very small ; I have, however,
obtained the following results : —

Number of Vibrations of the Wing per second.

Sparrow . 13

Wild duck . 9

Pigeon . 8

Hen -hawk, Brlteo vulgaris, a hawk called in England

and France the “buzzard” or “busard” . 5J

Sereech-owl . 5

Harrier, Circus rufus, marsh harrier of England,
buse of France . . 3

The frequency of the strokes varies according as the bird is starting,
is in full motion, or at the end of its flight. Some birds, as we know,
have periods when the wing is motionless, and when they move by means
of the momentum acquired.

It is interesting to observe the relative duration of the periods cl
ascent and descent of the wings. Contrary to the opinion expressed by
some observers, the descending period is generally longer than that of
elevation. The inequality of the two periods is especially evident in
birds which have large wings and make few strokes. Thus, while the
periods are almost equal in the duck, which has very narrow wings, they
are unequal in the pigeon, and much more so in the harrier.

The following figures exhibit the results obtained from several
species of birds : —

Species.

Total distance traversed during one
complete oscillation of the wing.

Propo

distf

Ascent.

rtional

mce.

Descent.

Duck .

6 -66 centimetres per second .

3-0

3-66

Pigeon .

7 5 centimetres per second .

3 0

4'5

Harrier .

215 centimetres per second .

8-5

130

AERONAUTICAL SOCIETY

It is more difficult than might be supposed to determine the precise
instant of the change of direction in the line traced by the telegraph.
The attraction of the magnet and the relaxation have an appreciable
duration, if the blackened cylinder turns with sufficient velocity to
measure the rapid motions which we seek to analyze. The inflections
of the line traced by the telegraph then become curves, of which it is
somewhat difficult to determine the precise origin. There is therefore
a limit to the precision of the measurements which can be made by the
electric method. I think that we cannot approximate by this method
nearer than jin of a second to the duration of a motion.

Another kind of signal allows the estimation of the frequency of the
stroke at the same time that it furnishes indications of the successive
action of the principal motive muscles of the wing.

Myographic method. — In 1867 I indicated a myographic method
which might be applied without mutilating the animal upon which the
experiment was performed. It consists in employing the swelling of a
muscle to afford evidence of its changes in length — that is to say, by its
contraction or relaxation. Muscles, not being sensibly compressible,
cannot change their length without at the same time changing their
transverse diameter. A rapid or short, feeble or energetic contraction of
a muscle, hence, is accompanied by an increase in diameter, affording
the same features of rate or intensity. At each descent of the bird’s
wing the great pectoral muscle thus exhibits an increase of size, which
can be indicated by the registering apparatus.

I have made use of flexible air tubes of India-rubber in transmitting
these effects, a method which has enabled me at times to register at some
distance the beating of the heart, the pulse, and the motions of respiration.

The bird flies in an enclosure fifteen metres square and eight metres
high. The registering apparatus being placed in the centre of this
enclosure, twelve metres of rubber tubing are enough to establish a
constant communication between it and the bird. A sort of corset is
applied to a pigeon ( see Fig. 16). Under this corset, between it and the
pectoral muscle, is placed a little contrivance intended to exhibit the
swelling of the muscle. It consists of a small shallow metal basin
containing a spiral spring, and closed over by a thin sheet of rubber.
This basin, thus closed, communicates with the transmitting tube.

Fig. 17.

Apparatus for exhibiting the contraction of the thoracic muscles of birds. The
upper convex face is formed of a sheet of rubber, held up by a spiral spring, and
is applied to the muscles. The lower face, in contact with the corset, carries
four little hooks which are caught in the cloth and hold the apparatus in its place.

6F GREAT BRITAIN.

Any pressure applied to the face of the apparatus depresses the
rubber. The air is forced out of the basin and escapes by the tube. If
the pressure ceases, the air re-enters the basin in consequence of the
elasticity of the spring which raises the rubber. An alternate inspiration
and aspiration is by this means established in the tube, and the motion
of the air transmits to the registering apparatus a signal of the more or
less intense pressure which has been exerted upon the rubber cover of the
basin. The registering apparatus I have used in all my experiments is
also composed of a basin, covered by a rubber membrane communicating
with the transmitting tube. The motion imparted to the first basin is
transmitted by the air to the rubber cover of the second. The motions
of the membrane of the receiving apparatus, amplified by a lever, are
written on the smoked cylinder. Fig. 16 represents the general arrange¬
ment of the experiment in which the electric telegraph and transmission
by air are exhibited together. We see the pigeon under experiment
furnished with its corset and apparatus for showing the movements of
its pectoral muscles. The transmitting air-tube ends at the registering
apparatus, which writes on a revolving cylinder. At the extremity
of the pigeon’s wing is an arrangement which opens or closes an
electric circuit as the wing rises or falls. The two wires of the
circuit are represented separately, and two cells of Bunsen’s battery are
seen in their connection with the helix, which, furnished with a lever,
registers the telegraphic signals of the motions of the wings. One
precaution is indispensable — the rubber tube which connects the bird and
the apparatus must be prevented from stretching. When the bird flies
it raises more or less of the tube, and if this is elastic it will become
elongated by its own weight, producing a rarefaction of the air contained
in the two receptacles, and the registering lever will trace muscular
curves on a descending line. To prevent this inconvenience, the tube
may be tied here and there to the telegraphic cord by means of ligatures,
taking care that the tube is a little longer than the cord, and that it is
not subjected to traction. These precautions being taken, nothing
prevents the successful transmission of signals. No trouble need be
taken in regard to the elasticity of the tube in a transverse direction ;
its walls are so thick that their elasticity is not brought into play by the
feeble changes of pressure to which the air they contain is subjected.

The bird is let loose at one end of the enclosure, the dove-cote in
which it is ordinarily kept being placed at the opposite end. The bird
naturally flies toward the latter. During its flight the tracings repre¬
sented by Fig. 18 are obtained.

The trace is seen to differ according to the kind of bird experimented
upon. However, in all the traces we perceive the periodical return of
two motions, a and b, which are produced in each vibration of the wing.
What is the signification of these two muscular actions ? It is readily
seen that the undulation a corresponds to the action of the muscle which
elevates the wing, and b to that of the muscle which depresses it.
This can readily be proved by comparing the trace of the muscular
action in the electric trace of the elevation and depression of the wing.
These two tracings, placed one under the other, show that the period of
elevation of the wing agrees with the extent of the undulation a, and the
period of deoiession with the undulation b.

Pig. 18.

Myographic tracings of the pectorals obtained from various kinds of birds during flight. I. Tracing of the tuning-
fork to be used in measuring the absolute duration of each muscular motion; this tuning-fork vibrates 200 times a second.
II. Tracing of the muscles of a pigeon obtained, as in Pig. 16. III. Tracing of a wild duck. IV. Tracing of hen-hawk
V. Tracing of a harrier.

AERONAUTICAL SOCIETY

OF GREAT BRITAIN.

But to establish this agreement we must take the unequal rapidity
of the transmission of the electric and aerial signals into account. We
may consider the electric transmission as instantaneous, while the aerial
transmission is at the same rate as the rapidity of sound through the
air, that is, 334 metres per second. If the points of the two styles are
placed vertically one above another, the tracings will not be exactly
superposed, but the electric signal will precede the other by a distance
corresponding to a certain fraction of a second, according to the length
of the tube which has been employed. We can even compute, from the
length of the air-tube, the amount of retardation, but it is more certainly
ascertained by a special determination for the particular tube which
may be in use. In a previous experiment, motions were simultaneously
transmitted by the tube and by electricity, and the discrepancy deter¬
mined. In the apparatus which I am using, the constant discrepancy is
•04 of a second. I should therefore set back the electric signals by a
corresponding distance, in order that they may agree with the signals
transmitted by the air-tube. Fig. 19 shows the superposed tracing from
a harrier after correction.

It is easy to understand how the undulations a and b are produced
in all the tracings of the muscles of birds. In fact there exist two
distinct planes of muscles in the upper part of the region investigated
near the end of the sternum. The most superficial is formed by the
great pectoral which lowers the wing, the deeper by the median pectoral
or elevator of the wing, the tendon of which passes behind the bifurcation
of the sternum to attach itself to the head of the humerus. The two
superposed muscles act by their swelling upon the apparatus applied to
them. The median pectoral swells when it contracts, signalizing the
undulation a by its action ; the great pectoral signalizes the lowering of
the wing in the undulation b in a similar manner.

We can verify the correctness of this explanation by a very simple
experiment. Anatomy shows us that the median pectoral is narrow, and
only covers the inner portion of the great pectoral along the keel of the
sternum. So if we displace the little apparatus which reveals the motion
of these muscles, and carry it further outward, it will occupy a region
where the median pectoral does not cover the great pectoral, and the
tracing only presents a simple undulation which corresponds to b in the
figures.

It is, therefore, sufficiently demonstated that the undulations a and
b, in the muscular tracings of the birds upon which I have experimented,
correspond exactly to the principal elevating and depressing muscles of
the wing ; but we cannot attach much importance to the form of these
tracings for deducing the precise nature of the motion effected by the
muscle. In fact, these motions appear to override one another. So the
relaxation of the median pectoral is probably incomplete when the great
pectoral oommences to act. We should expect no more from these
tracings than they naturally furnish, that is to say, the number of
vibrations of the wing, the greater or less regularity of its movements,
the equality, inequality, and energy of each of them. Restricting the
enquiry within these limits, the experiments show that the strokes of the
wings of birds differ in frequency and amplitude in the different moments

Fig. 19. — Line a represents the electric tracing of the ascent and descent of the wing of a harrier, as furnished by the apparatus.
Line 6 is a tracing of a tuning-fork vibrating 20rt times a second. Line c, correction of the electric tracing, which latter does not
represent the changes with sufficient abruptness in the figure (a) obtained directly from the wing. Line d, tracing of the action
of the pectoral muscles in the harrier by the air apparatus ; a', period of elevation' of the wing ; b', period of depression. Line e
will be hereafter referred to; it represents the vertical oscillations of the bird during flight.

Fig. 20.— Showing the difference in amplitude and frequency in the wing-strokes of a pigeon during a flight of fifteen metres.
To the left the extended traces indicate the movements at the commencement of flight. This tracing was recorded on a cylinder
which moved very slowly, allowing the record of a large number of strokes to be compressed into a small space.

AERONAUTICAL SOCIETY

OF GREAT BRITAIN.

of flight. At starting the strokes are fewer but more energetic ; they
attain, after the first two or three, a regular rhythm, which they lose at
the moment when the animal is about to alight.

We shall find in other experiments more complete indications of the
variation of the movements of the wing during the different periods of
flight.

Such are the certain indications which can be derived from the
method of signalizing established between the flying bird and the
registering apparatus. But if it is wise to guard our conclusions by more
rigorous experiments, it may at least be permitted us to attempt to
discover whether the tracings of these muscles cannot furnish us with
further information in regard to the motions from which they are derived.
I have elsewhere demonstrated that the form of the motion produced by
a muscle "when it is excited varies according to the resistance which this
motion encounters. Thus, in applying the myograph to the muscle of a
frog, I have seen that if contraction be impeded by an obstacle the
duration of the muscular shock becomes greater on account of that
obstacle. Theory, also, would foretell us, that if the muscle presents
certain modifications in the different phases of its contraction, the result
of unequal resistance overcome at different periods, the swelling of the
muscle should also present the same phases. If the tr.unng is the exact
impression of the motions produced by the muscle, it can inform us of the
nature of the resistance which the wing of the bird encounters in the
different phases of one of its vibrations.

Let us take the most simple example. As the median pectoral and
great , pectoral are very unequal in size, we may suppose that if the

resistance is equal in the two periods of elevation and depression, the

duration of the former would much exceed that of the latter ; and, as
exactly the contrary is the case, we may conclude that the rising wing
does not strike the air but cuts it apparently with its edge, so that the
resistance to the elevation is very feeble, and is very strong to the

depression of the wing. Now, if we examine the tracing of the

depression of the wing we shall find there, within certain limits, the
expression of the different amount of resistance which the wing encounters
in the different phases of its depression. It is necessary by previous
experiments to determine the effect of certain special kinds of resistance,
which we may call elastic resistance, in order to better understand the
signification of different forms of muscular motion.

Let us take the muscle of a frog, apply it to the myograph, and
excite contraction in it by means of electricity. The form of this
contraction varies in the following manner under the influence of
different kinds of resistance opposed to the action of the muscle : If a
weight be suspended to the muscle it gives the tracing a, Fig. 21. If it
encounter an absolute obstacle to all further diminution of length, after
a few instants of contraction it gives the trace b. Finally, if it encounters
an elastic obstacle, as a rubber thread, which presents a surmountable
resistance, the muscle gives the curve c. It seems as if these different
forms were sufficient to characterize the nature of the resistance that the
contraction of the muscle has had to overcome.

In the first case it is the inertia of a body ; now this body submitted

AEECWAtmOAL SOCIETY

to the muscular force during a limited period, should have an acedeifeted
motion at first and then a diminishing motion. This is precisely what
the form of the curve a indicates. In the second case it is not necessary
to explain how the horizontal line which forms the summit of the curve o,
expresses the cessation of all contraction in the presence of an absolute
obstacle. Lastly, in the curve c, the presence of an obstacle is betrayed
by a deflection of the curve ; that is, by a change in the rapidity of the
motion which produces it ; but the contraction does not cease because
the obstacle is not insurmountable, but it becomes slower on account of
the greater resistance presented.

I have been able to convince myself that in the above-mentioned
experiments the swelling of the muscle presents the same phases as its
change of length. In fact, I have transmitted to the myograph the
motion produced by the swelling of the muscle, and have obtained
tracings identical with the preceding. Finally, wishing to know if the
apparatus which I have used would faithfully transmit the different
phases of the swelling of muscle, I made the following experiment :
I applied the little drum which had served to obtain the tracings from
the birds (Fig. 18) to my own biceps muscle, fixing it exactly in plaee by
means of a bandage, and put it in communication with the registering
apparatus, I then made sudden voluntary motions, as similar as I could
make them to each other, but applied to overcome various forms of
resistance. In one case I lifted a weight ; in another my hand was
absolutely arrested in upward motion by being placed beneath a heavy
table ; in still another, I tied my hand to a fixed object with a rubber
band which, by a short flexure of my fore-arm, required the utmost
efforts of the muscle to irtretch it.

Now the tracings which express the swelling of the biceps in these
three experiments reproduce the three types represented in Fig. 21, and

Fig. 21.

show very clearly that voluntary exertions had been subjected to
different forms of resistance. I tried to force upon the muscles identical
motions in eacb case, which was always a short vigorous flexure, but the
nature of the resistance modified these muscular actions which were
intended to be similar to each other, and imparted to them the various

OF GREAT BRITAIN.

phases and durations which are exhibited in the figure. This being
settled, let us return to the muscular tracing of the great pectoral of the
bird. I have said that the exact commencement of this motion is
undetermined, the elevator of the wing not having fallen into repose
before the depressor commences to act, and if we would represent the
probable curve of the action of these two muscles from that which
the myograph obtains for us, it will be necessary for us to complete the
tracing by means of dotted lines as in Fig. 22.

Fig. 22.

Trace of the action of a harrier during flight : a, action of the elevating muscle ;
b, of the depiessing muscle. The dotted lines which descend to the axis of the
curve complete the probable form of the motions of the two muscles of the wing.

Thus reconstructed, the form of the curves of the elevator and
depressor reveals the nature of the resistance which each of these muscles
has encountered. The curve a of the median pectoral is that of a
muscle acting on a weight ; it seems to indicate that the inertia of the
wing is the only obstacle which the elevator muscle has to overcome.
The curve b shows us a deflection, during part of which the contraction
of the muscle takes a slower motion ; it is here that the resistance of
the air is interposed. These things happen, then, exactly as in the
experiments which I have made upon my own muscles and those of the
frog. But you may ask why the deflection of the curve is not produced
sooner ; and if the depressor muscle can rapidly contract for a certain
period before encountering sufficient resistailce from the air to impede
its motion. This is just what happens ; we have the proof of it in the
anatomical disposition of the attachments of the great pectoral muscle.
We shall see hereafter how the motion of the humerus around its
articulation is produced ; at present I will only say that in the first part
of its action the great pectoral in contracting produces a pivot-like motion
of the wing upon the head of the humerus, and that in this first motion
the muscle does not experience the resistance of the air which retards its
contraction an instant later.

AERONAUTICAL SOCIETY

The reader will perhaps consider that an inordinate number of
deductions are made from the forms of the curves of the muscles ; but
those who will familiarize themselves with the use of the registering
apparatus, and in particular with the myograph, will soon be convinced
that chance does not enter into the formation, of the curves, but that the
details should find their explanation in the dynamic conditions of the
production of muscular power.

Motions executed by the icing of a bird during flight. — We have seen,
in regard to the mechanism (if the flight of insects, that the fundamental
experiment has been that which has shown the trajectory of the point of
the wing in each of its evolutions. The knowledge of the mechanism of
flight flows, so to speak, naturally from this first idea. The same
determination is equally indispensable for the flight of birds, but the optic
method is here inapplicable ; the motion of a bird’s wing, while too rapid
to be followed by the eye, is not sufficiently rapid to form a persistent
impression of its entire trajectory upon the retina. The graphic method,
which I have hitherto employed, only furnishes impressions of motions
which happen to follow' a straight line, and it is only by combining this
rectilinear movement with the revolving cylinder with a smoked surface
that the expression of the rapidity with which the motion is effected at
each instant is obtained.

The problem is to find the means of registering on an immovable
plane all the motions which the point of a bird’s wing makes in space,
as if a style had been placed at the end of the wing, and this style
traced or rubbed on a piece of paper by its side. It is still further
necessary to have a figure of the same nature as the luminous figure of
the gilded wdng of an insect, that the piece of paper on which the trace
is to be made shall remain motionless in regard to the centre of motion
of the wing of the flying bird, or in effect that it shall follow the bird in
all its phases of impulsion' through space.

Now, physios teach us that all motion susceptible of registration in
one plane can be generated by the rectangular combination of two
rectilinear motions. The tracings obtained by Koenig by arming a
vibrating Wheatstone’s rod with a style, the luminous figures of musical
chords which M. Lissajous has produced by the reflection of a ray of
light from two vibrating mirrors perpendicular to one another, are well
known examples of the formation of a plane figure by means of two
rectilinear movments. Thus, admitting that the motions of elevation
and depression of the wing can be transmitted at one time, as well as
the back and forward motions of this organ, by supposing that a writing
style can simultaneously receive the impulse of these two motions,
perpendicular to each other, this point will write on the cylinder the
exact figure of the motions of the bird’s wing. I tried at first to construct
an apparatus which would thus transmit such a motion to a distance and
register it, without concerning myself with the way in which I might
apply this rather weighty mechanism to the bird.

Fig. 23 represents this provisional apparatus, the description of
which is indispensable for the comprehension of the second mechanism,
which I shall describe hereafter. Upon two solid feet, carrying vertical
supports, are seen two horizontal arms parallel to each other. These are

OF GREAT BRITAIN

two aluminium levers which, by the transmitting apparatus to be
described, should both execute the same motions. Each of these levers
is mounted on a ball-and-socket joint, or double articulation, which

Fig. 23.

Apparatus intended to transmit to a lever at a distance all the motions
executed In another lever around one of its extremi Aes.

AERONAUTICAL SOCIETY

permits all kinds of motion ; thus each lever can be carried above, below,
to the right, or to the left. It can by its point describe the base of a
cone of which the joint will be the apex. In fact, it will execute any
kind of motion which the experimentor may choose to impart to it. It
is also necessary to establish the transmission of motion from one lever
to the other at a distance of ten or fifteen metres. This is done by
means of a process with which the reader is already familiar — the use of
drums and air tubes.

The lever, which is seen at the left in the figure, is fastened by a
metallic arm articulated at one of its extremities to the membrane of a
drum placed below it. In the vertical motions of the lever the membrane
of the drum rises or falls by turns, producing a throbbing motion of the
air in another drum through a long tube, which establishes a communica¬
tion between them. In the apparatus to the right in the figure,
the second drum is placed above the corresponding lever articulated
with it, and faithfully transmits all the motions which have been
imparted to the first drum to the left. These movements will be in the
same direction in both levers on account of the inversion of the position
of the drums. If we depress the first lever it presses down the membrane
of the drum below it, inducing a pressure which lifts the membrane of
the second drum and consequently lowers the second lever ; conversely
the elevation of the first lever produces an influx of air, which raises the
metnbrane of the second lever.

Proceeding in the same manner to transmit motions in a horizontal
plane, I have placed at the right of one of the levers and at the left of
the other a drum with the membrane in a vertical plane, which imparts
lateral motions to these levers ; these motions are transmitted by a
special air-tube, as before. In the apparatus thus constructed, if we
move the end of one of the levers with the finger, the other lever will be
seen to execute the same -movements with perfect fidelity. The only
difference consists in a slight diminution of amplitude. This happens
because the air contained in the tubes and drums is slightly compressed,
and in consequence docs not transmit the whole of the motion which it
receives. It is easy to remedy this defect, if it be one, by placing the
ball-and-socket joint a little nearer the point whence the motion is
transmitted to the second lever. But it is better not to attempt too
great amplification, because the friction is thus augmented and the force
which should overcome it is diminished.

After having determined that the transmission of such motion can
be effected in a satisfactory manner by means of this apparatus, I have
sought for the means of tracing these movements upon a plain surface.
The difficulty which before presented itself when I endeavoured to apply
tne graphic method to the study of the wing-strokes of insects, again
appeared, but this time there was no means of eluding it, and I contented
myself with partial tracings. The point of the second lever described a
spherical figure in space which could not be tangent, except as a point,
to the smoked surface, which should receive the trace. In consequence,
I should have to register the projection of this figure on the plane.
Helmholtz has also encountered the same difficulty in the construction
of his myograph, and had solved it by causing the point of the writing

OF GBEAT BEJXAUf.

style to rub continually on the smoked surface by means of a weight.
But as I could not attach a weight to the extremity of my lever,
I resorted to the following expedient, shown at the end of the lever in
Fig. 24. It is large at the base in order to resist all lateral deviations

from friction ; this base is fixed on a vertical piece of aluminium which
is attached to the extremity of the lever. In this way the point of the
contrivance, which performs the office of a style, is situated exactly
opposite the end of the lever whose motions it registers. If the lever be
elevated and takes the position indicated by the dotted lines in Fig. 24,
in traversing this space it has described the arc of a circle, and its
extremity will be no longer on the same plane as before, but the
elasticity of the contrivance wall have carried the point of the style
forward, and it will therefore continue to be in contact with the plane
upon which it is tracing. Thus the lever elongates or shortens according
as the case requires, and its point continually rubs upon the plane.
I should add that the surface upon which the tracings are received is of
finely polished glass, and that the contrivance which I have used is so
delicate that the pressure which it exercises produces scarcely any
friction.

The apparatus being thus constructed, it must be submitted to
verification, to ascertain whether the motions are faithfully transmitted
and registered. To do this both levers of Fig. 23 are furnished with
similar styles placed against the same smoked glass ; and moving one
of the levers with the hand, for instance, so as to write my name, the
other lever should reproduce the same signature. It frequently happens
that the transmission is not equally good in both directions, which is
perceptible by the deformity of the transmitted figure, which is increased
more or less in height or breadth. This deficiency can always be
corrected, since it is due to the membrane of one of the drums being
stretched more than that of the other, and hence yielding' less easily to
pressure. It is very easy to equalize the tension by tightening the
membrane of the other drum until the figure traced by the first lever U
identical with that traced by the second.

AEE0NAT7TICAL SOCIETY

The modifications by means of which I have rendered this trans¬
mission applicable to the study of the motions of the wing of a flying
bird, are as follows : —

The apparatus necessarily being heavy, it required a large bird to
carry it. Strong adult harriers served for the experiments. I fixed a
light strip of wood upon the bird’s back, upon which the apparatus was
placed, by means of a kind of corset, which left the wings and feet free.
That the lever might faithfully execute the same motions as the bird’s
wing, the joint of the lever should be placed in contact with the humeral
articulation of the harrier. As the presence of the drums by the side of
the lever does not permit this immediate contact, I had recourse to a
parallelogram, which transmitted to the lever of the apparatus the
movements of a long arm of which the centre of motion was very close
to the articulation of the bird’s wing. Finally, to obtain an identity of
motion between the arm and the harrier’s wing, I fixed on the bastard
wing, that is to say, on the metacarpal portion of that organ, a well cut
screw-vice, furnished with a ring, through which passed the steel arm
of which I have just spoken.

Fig. 25 represents the harrier flying with the apparatus in question ;
below hang the transmitting tubes of the registering apparatus.

Fig. 25.

Harrier ll.ving with the Apparatus, winch transmits the motions described by
the extremity of its wing.

After a great many fruitless attempts and changes of construction
of the apparatus, which, being very fragile, broke at almost every flight
of the bird, 1 succeeded in obtaining satisfactory results. During flight
the registering lever described a kind of ellipse, but I was obliged to
give up registering this figure upon a stationary glass. The motions of

OF GREAT BRITAIN.

the wing differing at different moments of flight, the style did not pass
over the same points, and 1 obtained a very confused tracing. I then
resolved to use a glass moving horizontally at a uniform rate in order to
obtain an extended figure, which I could afterward submit to a geometric
correction, and thus obtained as it would be if traced on a stationary-

surface a figure for each instant of
flight.

Fig. 26 represents one of the nume¬
rous tracings which I have thus obtained.
The perfect uniformity of these tracings
gives me entire confidence in their cor¬
rectness. To analyze the meaning of
this curve it is necessary to know how
the bird flies, how the apparatus is
arranged, and in what direction the
smoked glass moves while receiving the
tracing. The observer being placed
opposite the glass on the smoked side,
sees it move from the right to the left ;
between the glass and himself is a
tracing apparatus with the lever rubbing
upon the smoked surface directly in front
of him. The bird flying from right to
left, in a plane parallel with that of the
glass, carries the lever of the apparatus
on his right wing, so that the respective
levers of the two machines are always
parallel to each other. This being
known, the tracing should be read from
left to right. We have seen that the
tracing consists of a kind of ellipse,
which the motion of the glass extends
into a spiral. The movements, more
extended at the beginning of flight,
gradually lose a little of their amplitude,
and retain a uniform character for some
time.

This figure somewhat resembles
that which we obtain from a Wheat¬
stone's rod, according to the unison
which traces the ellipse which its point
describes upon a surface moving from
right to left. Fig. 27, showing the
tracing of this rod, admits the comparison
of the two.

The wing of a harrier thus describes
a sort of ellipse, but it is necessary to
determine more exactly its shape, and
to correct the error caused by the
motion of the glass plate.

AERO^trtlCAI, SOCIETY

Pig. 27.

Ellipse traced by a Wheatstone’s rod upon a turning cylinder.

Such a correction is impossible unless we know the elevation attained
by the wing at the end of successive and equal intervals of time. This
pnce obtained, if we trace parallel horizontal lines representing the
position of the wing at each of these successive moments, these lines will
cut the descending curve at points which correspond to the successive
equal intervals of its course. It is clear that if these successive points of
the curve have been produced at equal intervals of time, each of them,
under the influence of the motion of the glass plate, will have a constant
deviation toward the right, bearing a stated relation to the preceding-
point. The correction thus consists in carrying the second point back
toward the left twice this amount, the third point three times this amount,
and so on. The ascending portion of the curve should also be submitted
to this correction, and similarly each part of the tracing. But it is
precisely the height which the wing attains in the different ascending
and descending motions of its course which we do not know ; but this
want can be supplied by the apparatus in the following manner : —

Since the principle of this mechanism is founded upon the trans¬
mission of two motions, perpendicular to each
other, vertical and horizontal, it suffices to
suppress the transmission of the horizontal
motion to obtain the curve of elevation imme¬
diately ; that is to say, the expression of the
height of the wing at each instant of its course.

For this I obstruct the tube of lateral trans¬
mission, let the bird fly, and obtain the curve
of the heights of the wing at each moment.

The correction being made, and Fig. 26
being selected to show the course of the point
of the wing during one of its evolutions, and
projected upon a stationary plane, we obtain
Fig. 28.

The arrows indicate the direction in which
the wing moves. Course in space of the

Is this the form characteristic of all birds ; extremity of the wine, re-
or is it only that of tl^e hai rier in the conditions °m t*'° lnot*<" °*

of flight in which it has been placed ■

OP GBKAT BBITAIW,

The last supposition appears to be the most probable ; we can see,
even while comparing the form of the tracing at different instants of its
flight while under experiment, that the ellipse is greater and more
open in the first strokes of the wing than in the last. It is, however,
necessary to except the second stroke of the wing, which has given me a
narrower ellipse than in any other in all the experiments which I have
made. I do not know to what this special form is to be attributed, but
have thought it worth while to mention it on account of its constancy.

Of the rotation of the humerus and the changes of the plane in the
wing during flight. — The wing of a bird, like that of an insect, must meet
with a sufficient resistance from the air in its motion upward and down¬
ward to incline its flexible portion, namely, that which forms the webs
and coverts. This cause does produce, a change of the plane of the wing,
but there is another even more powerful, for it places the wing at the
outset of the depressing motion in a favourable position for the double
propulsion which iB produced. I refer to the pivot motion which the
humerus executes around its axis at each contraction of the great
pectoral. It is enough to examine the bony crest on which the large
tendon of the great pectoral is inserted, and to consider that this crest
is situated on the anterior edge of the humerus, to comprehend that the
action of the great pectoral, whose fibres are carried backward and
downward, should produce a rotary motion of the humerus around its
longitudinal axis. The conformation of the humeral articulation is
perfectly adapted to this motion. Finally, the existence of this rotation
is rendered still more necessary by the resistance which the air presents
to the back of the wing and opposes to the descent of its feathered
portion. We can demonstrate the existence of this motion and measure
its extent by means of the registering apparatus. But I have thought it
best to defer these researches, especially as they necessitate the
construction of special apparatus, which would require numerous experi¬
ments, and would produce, after all, results of very slight importance.
In fact, we are enabled to deduce from the attachment of the muscles
the nature of the motion which they produce, and this deduction is
especially easy.

I have always sought to verify the existence of this rotary motion of
the humerus, and to measure its extent, by the application of electricity
to the muscles of the bird. In the experiment for measuring the static
power developed by the contraction of the great pectoral muscle,
previously described, I noticed that at each excitement of this muscle the
humerus executed a rotary motion upon its axis. I fixed in the humerus
a rod, • erpendicular to its axis, and was enabled, by the angle formed
by the two positions of this rod, to demonstrate that the rotation in the
harrier corresponded to an angle of thirty-five or forty degrees. It
seemed that the limits of this angle were fixed by the attachments of
the median and great pectoral muscles. If .traction be exerted upon the
two antagonistic muscles of a newly-dissected bird, it will be seen that
the median pectoral raises this member so that its upper face is turned
somewhat backward. The action of the great pectoral changes this
position of the wing completely, and carries its upper face strongly
upward and even a little forward. These expressions, upward and

AEKONAUTIOAL SOCIETY

downward, are relative to a plane cutting the bird into a dorsal and a
ventral half ; but this plane, doubtless, is not entirely parallel with the
horizon during flight. But it is certain that the resistance of the air
should give a much more pronounced deflection to the feathers during the
more rapid descent of the wing.

The most difficult to measure of the influences which change the
plane of the bird’s wing is that which relates to the pressure of the air on
the feathers. Perhaps it may not be impossible to devise an apparatus
capable of measuring it, but it so varies with the variations of the
velocity with which the wing is lowered, that any measurement which
might be obtained would be only the expression of a particular case. It
is very probable, on the contrary, that the change of plane due to the
action of the pectoral muscles is a much more constant phenomenon.
We can infer the action of the two motions of the bird’s wing from what
has been said of the mechanism of the flight of insects. It is evident
that the descent of the wing will have the double effect of raising the
bird and of imparting to it a horizontal motion. As to the ascent of the
wing its office cannot be the same, because the imbrication of the
feathers does not offer a resistant surface to the air.

Everything tends to show that the ascending wing cuts the air with
its anterior edge, but, as we shall see, another phenomenon occura which
uplifts the body of the bird during the elevation of the wing ; this is the
transformation of the impulse which the bird has acquired during the
lowering of the wing. This impulse is changed tn rising, by a mechanism
analogous to that which raises the toy kite.

In a remarkable study of the flight of birds, M. Liais has been led,
through observation and deduction, to adopt this theory, to which the
experiments about to be described, I trust, will add new proofs in its
favour.

Before leaving the subject it is necessary to mention the existence
of certain other motions in the flight of small birds. I refer to the
folding and unfolding of the wings. But the existence of these motions
does not seem to be constant, and the eye cannot perceive the least trace
of them during the flight of the large birds upon which I have experi¬
mented. I shall, therefore, omit the study of these motions, and of their
possible effects, and restrict my conclusions on the mechanism of flight
to a certain number of determinate species of birds.

The study of the motions of the wings of birds during flight
necessarily includes the effect produced by each of these movements.
We are tempted to deduce these effects from the nature of the motions
which generate them, but it is safer to obtain the solution of this
complicated problem from experiment. Two distinct effects are produced
during flight : first, the bird is upheld against the force of gravity ;
second, it is propelled horizontally. Is the bird in the air sustained at a
constant elevation, or is it rather subject to oscillations in the vertical
plane? Does it not exhibit, by the intermittent effect of the strokes of
its wings, a series of ascents and descents, the frequency and extent of
which cannot be observed by the eye ? Is not the bird also subjected to
a variable velocity in its horizontal course? Does it not receive a
jerking motion from the action of its wings ? These questions can be

OF QREAT BRITAIN.

solved by experiment in tbe following manner : Since we possess the
means by which distant motions produced by pressure exerted upon a
drum filled with air are made to record themselves, we must seek to
connect the movements which we would study with a pressure of this
kind. The oscillations which the bird executes in the vertical plane
should be made to produce alternately strong or feeble pressure on the
membrane of the drum, according as the bird rises or falls. The same
should be done in seeking the variations of its horizontal velocity.
Suppose that a flying bird carries upon its back a light metallic drum,
like the one already described ; that the membrane of this drum be
Turned upward, and that this instrument be put in communication with
the registering apparatus by means of a long tube. If the membrane of
the drum freely partakes of the motions of the bird it will not produce
any displacement of the air in the apparatus, and the registering lever
will remain motionless. But if we prevent the membrane from partaking
of all the motions of the bird, if we can give it a tendency to remain at
rest while the drum is moved, motion will be produced in the air with
which the drum is filled, and the signals will be registered by the lever.
Now, we can produce this tendency to remain at rest upon the membrane
by loading it with an inert body, such as a disc of lead.

Fig. 29 shows the drum with an inert mass upon its membrane.
This mass is formed of discs of lead, of which a certain number can be
added or taken off, until the apparatus responds satisfactorily to the
motions of vertical oscillation imparted to it. In this arrangement the
movements in the horizontal plane are without influence upon the
apparatus. If the drum is suddenly raised, the inert body, not
participating in this elevation, depresses the membrane exactly as if the
mass itself had been depressed and the drum had remained motionless.
Conversely, when the drum descends, the inertia of the mass resists the
motion as if it or the membrane had been raised and the drum had
remained motionless. We may remark that the movement of the lever
is in the same direction as that of the drum ; that is to say, if the drum
be raised the lever also raises itself. It may happen with an apparatus
of this kind, that in the motion of the wings rubbing may be produced
on the membrane of the drum which will make confusion in the signals.
To avoid this I cover the upper part of the apparatus with a metallic
network, as seen in Fig. 29. The drum is there represented in the hand,
held by the transmitting tube connecting with the registering apparatus,
ff the drum is moved in the vertical plane the lever is seen to move in
the same direction, at the same instant of time, and with an amplitude
proportionate to the motions of the hand. If, on the contrary, we give
the mass a lateral motion, no effect is produced upon the lever and no
signal is made. But it may be said that an inert mass placed on an
elastic membrane tends to execute vibrations peculiar to itself, and that
the apparatus will transmit these vibrations of the mass of lead and the
membrane which carries it independently of the oscillations of the bird.
How shall we get rid of this complication ? The law of vibrations teaches
us that the duration of the double period of each of them varies with the
weight of the vibrating body and with the elastic force of the lamina
which carries it. The greater the mass and the feebler the elasticity

Fig. SO.

Line 1. Chronographic trace of a tuning-fork vibrating 100 times a second. 2. V ertical oscillations of the wild duok during
flight. S. Oscillations of the hen-hawk. 4. Of the screech-owl. 5. Of the harrier.

OF GREAT BRITAIN,

AERONAUTICAL 80CIETY

mission of motions, which are not too slow, may be obtained, for instance,
such as last less than half a second. It is not necessary, either, that the
instrument should be applied to the study of the oscillations of all species
of birds.

But to make sure of the accuracy of the apparatus it should be
verified by the method much like that which I have used to correct all
my apparatus. This consists in making directly, by hand, the tracing of
the motion which I have imparted to the weighted drum, and observing
whether the registered motion was the same as the first.

Experiments made upon different kinds of birds, ducks, harriers,
hen-hawks, and owls, have shown me that, in relation to the intensity of
the oscillations in the vertical plane, very varied types of flight exist.

Fig. 30 shows tracings, furnished by different kinds of birds, upon a
cylinder turning at a uniform rate, and contrasted with a tracing
produced by a tuning-fork making 100 vibrations per second. These
tracings enable us to estimate the absolute and relative duration of the
oscillations of flight in these different birds. It follows from these
figures that the frequency and amplitude of the vertical oscillations vary
a good deal with the kind of bird under consideration.

Fig. 31.

In the upper half is Seen superposed the musenlar tracing and that of the
vertical oscillations in a wild duck. Below the undulation a, which indicates
the elevation of the wing, is seen a vertical oscillation ; and another, below b,
which indicates the lowering of the wing. In the lower portion are the same
tracings obtained from a harrier; here the oscillation at a, which corresponds to
the elevation of tho wing, is less marked than in the duck.

OF GREAT BRITAIN.

To better comprehend the cause of these variations, let us register
at the same time the vertical oscillations of the bird and the action of the
muscles of its wing. If we make this double experiment upon two birds,
differing in their manner of flying, such as the wild duck and the harrier,
the tracings represented by Fig. 31 will be obtained.

The duck presents two energetic oscillations at each revolution of its
wing ; the one at b, at the moment when the wing relaxes, is easily
understood ; the other, at a, at the moment when the wing rises. To
explain the ascension of the bird, during the time of elevation of the
wing, it seems to me indispensable to call in the action of the boy s kite,
previously alluded to. The bird, moving forward with acquired velocity,
presents its wings to the air in an inclined position similar to that of the
kite, and thus transforms its horizontal force into an ascending one.

The flight of the harrier presents the ascension which accompanies
the elevation of the wing in a smaller- degree. May not the cause of
this difference be recognized as a smaller relative inclination of the wing
toward the horizon ?

Determination of the different phases of the evolution of the mng to
which the vertical oscillations correspond. — The interpretation of. these
curves throws light at once upon the experiments made on the variations
of the transformation of velocity in the bird, at different moments, during
the evolution of the wing. ,

But, before going further, we may remark that the preceding
experiment furnishes a very precious lesson in the theory of flight.. In
fact, if the bird excutes a series of ascents and descents, the duration of
the descending period will approximately inform us of the amount of. the
positive work which the bird must perform to rise again to the height
from which it fell, and we see that the duck, which makes nine vibrations
of the wing per second, executes two vertical oscillations during each
vibration, or eighteen in a second. Each oscillation is composed of a rise
and fall, so that each descent of the bird cannot last more than one
thirty -sixth of a second. Now, if we subtract the effect produced (as in
a parachute) by the outspread wings of a bird, we find that a body which
fo.Ua during one thirty -sixth of a second traverses only fifty-two milli¬
metres. This fall repeated eighteen times a second constitutes a total
rise of 9 36 centimetres, necessary to maintain the bird in the same
horizontal plane during one second.

In the tracing of the harrier, the descents are less than in the wild
duck, probably on account of the large surface of the wings of this bird.

Determination of the variations of the rapidity of JUgbj,.—' The second
question to be solved relates to the determination of the various phases
of rapidity of flight. The solution can be found in the following manner :
If the weighted drum be placed upon the bird’s back in a vertical plane
perpendicular to the direction of flight, it will be insensible to vertical
oscillations, and will only indicate those of forward and backward ; also,
by turning the membrane of the drum forward it is clear that if the
advance of the bird is accelerated, the retardation of the weight on the
translation of the apparatus will produce a crowding of the air in the
second drum, and an elevation of the registering lever, while a relaxation
of the effort of the bird will bring about a descent of the registering

AERONAUTICAL SOCIETY

lever. Experiments upon the kinds of birds previously mentioned
furnish tracings anal ago us to those of the vertical oscillations. If it is
true, as I suppose, that the vertical oscillation of the bird at the moment
of raising the wing be due to the upward transformation of velocity, by
obtaining, simultaneously, the tracing of the vertical oscillations and
those of the variations of velocity, we shall have the means of confirming
this theory. When obtaining at one time the two kinds of oscillations
in the flight of a harrier, I have seen that the phase of descent of the
wing resulted both in the elevation of the bird and the acceleration of its
speed. This effect is the necessary consequence of the inclination of the
plane of the wing at the moment of its descent, as we have previously
shown in the flight of insects. As for the phase of elevation of the wing,
it is proved that during the slight ascension which it produces the speed
of the bird is diminished. In fact, the curve of the variations of rapidity
falls as soon as the bird begins to rise. This is, then, a confirmation of
the previously suggested theory of the upward transformation of the
speed of. birds. Thus by this mechanism the descending stroke of the
wing creates the force which produces the two oscillations of the bird in
the vertical plane. The downward stroke directly produces the ascent
which is synchronous with it, and indirectly by creating the velocity
which prepares for the second vertical oscillation.

Simultaneous tracing of the two kinds of oscillation of the bird. —
Instead of representing each kind of oscillation separately, I have thought
that it would be more instructive to obtain a single line which, by its
curves, should represent both of the movements which the body of the
bird executes in its course through space. The method which has been
used to obtain the curve of the point of the wing, with some modifications,
can be made to furnish a simultaneous tracing of both kinds of motion.
For this both drums must be connected with the same inert mass, and
placed at right angles to each other. Turning back to Fig. 23, which
shows the two levers connected by tubes which transmit to the one all
the motions executed by the other, when any motion is imparted to the
first lever, the second lever reproduces the same motion in the same
direction. Now, let us charge one of the levers with a mass of lead,
and, taking the support of the apparatus in the hand, make it describe
some motion in a plane perpendicular to the direction of the lever. W e
see that the lever No. 2 executes directly opposite movements. In fact,
since the motive force which acts on the membranes of the drums is
simply the inertia of the mass of lead, and since this mass is always
behind the motion given to the apparatus, it is clear that if the whole be
raised the mass will keep the lever down ; if the whole be lowered, the
mass will raise the lever ; if it be carried forward, the mass will hold
back the lever, &c. Now, the second lever, executing the same motions
as the first, will give curves which are directly the opposite of the
motion which has been given to the support of the apparatus. This
being settled, nowr for the experiment : — For this I take the apparatus
represented on the back of the harrier in Fig. 25 ; 1 remove the rod
which receives the motion of the wing, and the parallelogram which
transmits it to the lever. I keep only the lever connected with the two
drums and the mounting which attaches it to the bird’s back. I fix a

Fig. 32.

Or GREAT BRIT AIK,

mass of lead on this lever and,
let the animal fly. The tracing
obtained is represented by Fig. 32.

The analysis of this curve is
at first sight extremely difficult.
I hope, however, to succeed in
showing its signification. It is
traced on the cylinder under the
same conditions as Fig. 26, show¬
ing the different motions of the
point of the wing. The glass
plate moves from the right to the
left ; the tracing is read from left
to right. The head of the bird
is toward the left ; this flight is
in the direction of the arrow.
We can divide this figure by
vertical lines passing through
homologous points, cutting it
either at the top of the loops or
at the summit of the simple
curves, as represented at the
points a and e. Each of these di¬
visions encloses sinplar elements,
although their development is
unequal in different parts of the
figure. For the present we shall
neglect these details.

It is evident that the peri¬
odical return of similar forms
corresponds to a return of the
same phases in an evolution of
the bird’s wing. The division a t
thus represents the different mo¬
tions of the bird during an alar
evolution.

Let us recollect that in the
curve which we are analyzing
all the motions are the reverse of
those which the bird really
executes. The two vertical oscil¬
lations, the great and the small,
should then be represented by
two downward curves. It is easy
to recognize them in the great
curve afi'b and the small curve
cde. Thus the bird rises from
a to b, falls from b to c, again
rises from c to d, and re-descends
from d to e; but these oscilla-

AEBONATTITCAL SOCIETY

tions encroach on each other, producing the loop cd. The oscillation ede
partly covers the first anteriorly. This is a proof that the indications of
the curve are the reverse of the true motion ; for, at this moment, the
bird recedes, or at least relaxes its course. As the apparatus is only
sensible of changes of velocity, it is clear that the tracing does not take
the uniform rapidity of the bird into account, but indicates acceleration
as a forward movement and retardation as a retrograde movement. This
figure, then, sums up all the preceding experiments which we have made
on the motions of the bird in space. It is here seen that the bird at
each evolution of its wings rises and falls twice successively ; that these
oscillations are unequal ; the larger, as we know, corresponding to the
depression of the wing, the smaller its elevation. It is also seen that
the ascent of the bird during the raising of the wings is accompanied by
a retardation of its speed, which justifies the theory by which this
ascent has been considered as made at the expense of the bird’s acquired
velocity. But this is not all ; this curve also shows us that the motions
of the bird are not the same at the beginning and end of flight. We
have seen already (Fig. 20) that the first strokes are more extended than
the others ; we now see that at first — that is, at the left of the figure —
the oscillations produced by the descent of the wing are also more
extended. But theory foretold that the oscillation of the elevation of
the wing being derived from the acquired speed of the bird should be
very feeble at the beginning of flight when the animal has acquired but
little impetus. The figure shows us that this does happen, and that at
the beginning of flight the second oscillation (which forms the loop) is
very insignificant.

At last, then, we are in possession of the principal facts upon which
the study of the mechanical power developed by the bird during flight
can be established, and we see that it is during the descent of the wing
that the entire motive force which sustains ana directs the bird in space
is created.

OF GREAT BRITAIN.

CONCLUDING REMARKS.

One of the most important events in connection with
Aeronautics during the past year has been the trial of
M. Dupuy de Lome’s navigable balloon. This balloon was
constructed by M. de Lome for the Government of National
Defence, at a cost of £1600., and was intended to open a
communication between Paris (then besieged by the
Prussians) and the departments. But, owing to unavoidable
delays, it was not finished until just four days before the
capitulation. Then came the Commune, and all the disorga¬
nization which followed it ; and it was not till the
2nd February, 1872, that M. de L6me was able to ascend
on a trial trip from Fort Neuf at Vincennes.

Before describing the balloon and the ascent, it may be as
well to say a few words as to the enu which the eminent
engineer proposed to himself. He did not pretend to be
able to successfully contend with the wind, but only to
deviate from the direct set of the wind when running before
it; so if the wind set straight from Paris to Brussels an
ordinary balloon could only land at some point between Paris
and Brussels, but with M. de Lome’s balloon the aeronaut
might deviate from the wind’s course, and descend at London
or Cologne as he saw fit.

The following is a description of the balloon as given in
M. de Lime’s report read before the Academy of Science.
The form of the balloon is oval, its diameter being about

wo-fifths of its horizontal length.

Total length from end to end . . 118ft. 6in.

Diameter at the point of greatest circumference. 49ft. 2in.

Diameter of the screw . . . .... 29ft. 6in.

Number of blades . . . 2

Pitch of screw . 26ft. 8in.

.76

AJEHOKA.TJTIOAL SOOHETY

The rudder is a plane triangular surface, made of
unvarnished calico, and is kept in its place by a horizontal
beam six metres long at its lower extremity. It can turn
easily on its forward extremity. The height of the rudder is
5 metres, and it has a superficies of 15 square metres.
The car is of wicker-work, and of sufficient size to contain
comfortably the windlass for the screw, and eight men to
work it ; the ventilator with which to manage the small bal¬
loon (we shall have to speak of this presently), and the man
who attends to it. In all, fourteen persons can be carried. The
driving screw is directly carried by the car. The shaft of
the screw is a hollow steel tube. This shaft is constructed
so as to allow of the screw being easily dismounted when a
landing is effected. The rudder is fixed to the balloon itself,
and the screw, as we said, is below it, and immediately
attached to the car. Two blades only are used in the screw
instead of four, because when the ground is touched the two
blades can be placed horizontally, so as to escape injury.
Were there four blades, the screw would be almost certain to
be broken at every landing. The windlass which turns the
screw is worked by four, or, if necessary, eight men, in a
similar manner to the steering wheel of a ship, only the
wheel is placed parallel to the axis of the car, instead of at
right angles to it, in order to lessen the rolling occasioned
by the movements of the men working the windlass.

The material of which the envelope of the balloon is
composed is white silk, weighing 52 grammes, not quite
2oz. to the square metre; and a coarser lining weighing
40 grammes the square metre, and seven coats of india-rubber,
which together weigh 180 grammes, a little over 6oz. the
square metre. Thus the whole weight of the external web
of the balloon is 272 grammes, about 9oz. to the square
metre. In order to render the web of the balloon totally
impermeable to the hydrogen gas with which it is inflated.

OF GREAT BEITAIW.

the silk was painted over with a sort of gelatinous compound*
invented by M. Dupuy de Lome. The total weight of the
two balloons when ready to start was 570 kilogrammes, or
rather more than half a ton. The web of the balloon was
reckoned to be capable of supporting a pressure of over
2000 pounds to the square yard. The smaller balloon is,
more correctly speaking, only a portion as it were of the
larger balloon. It is formed by means of an inner skin,
separating the bottom of the balloon from the rest. This
compartment occupies about one-tenth of the whole capacity
of the balloon, and serves to keep it stiff and of the
required shape. By these means M. Dupuy de Lome has
attained the two ends he proposed to himself, viz., first,
permanence in the shape of the balloon ; and, secondly,
an axis unquestionably parallel to that of the force of
propulsion.

M. de Lome calculated that the resistance to the balloon
at a speed of 7ft. 5in. per second, or 8 kilometres an hour,
would be 25lb8., and that this speed could be obtained by

2 1 revolutions of the screw per minute.

We will now describe the ascent: — There was half a gale
of wind blowing at the time, and the screw had been
slightly damaged. The inventor did not hesitate, however,
to make the ascent. The end justified his confidence,
for not only was he able to land near Noyon, in the Depart¬
ment of the Oise, some seventy miles north-east of Paris, but
his balloon more than answered his expectations. The
screw, when worked by four men, drove the balloon 8 kilo¬
metres (about 5 miles) an hour quicker than the rate at
which the wind was blowing. By the use of the rudder the
course of the balloon could be altered 1 1 degrees either way
from the set of the wind, making a total deviation of

22 degrees. The screw when worked by eight men drove
the balloon at the rate of 10 \ kilometres per hour. The

AEBOWAUTICAi flOOrEXY

number of revolutions at this speed was 27^ per minute, and
the power required was 26,400 foot-pounds per minute.
The slip of the screw was 24 per cent. Although the speed
obtained was not great compared with tbe velocity of an
ordinary wind, yet by employing an 8-horse power engine in
place of the eight men, a speed of 22 kilometres per hour
would have been obtained, which would enable the balloon
not only to deviate from the wind, but to struggle against it
when moderate.

Experiments with aerial screws have occupied attention
during the past year. One correspondent, Mr. Ling6eld, has
constructed a piece of apparatus consisting of two superposed
screws, rotating in opposite directions ; he found that there
was no advantage in using four blades, but that an equally
good or better effect could be obtained by means of two blades
by which he caused a lifting force of 14£lbs. by his own
muscular strength. Having a suspicion that the friction of
the surface of the fabric absorbed a considerable per centage
of the power, he pasted tissue paper over the calico of the
vanes, and thus increased the lifting force to I8lbs.

This proves the importance of attending to the question of
friction in aerial mechanism ; to diminish it as far as possible
on the surfaces of supporting planes gliding on air, and in
reciprocating or oar-like propellers, when possible, to utilize
friction as an aid in gaining additional abutment or hold on
the air, a principle probably made use of by some birds.

Similar experiments have also been made in Paris by which
a lifting force of 26£lbs. was obtained. But these results,
though obtained by independent experimenters both here and
on the Continent, must not be taken as conclusive of a
maximum effect, for probably a far higher reaction- or force
against gravity may ensue from more suitable forms of screw,
and in the best means of giving them* motion.

One difficulty has been a ready means of varying the angle

OT GRXAT BRITAIN.

or pitch of the screw, in order to suit the velocity of .rotation
and the force applied. Mr. Wenham has proposed a simple
kind of screw for this purpose, constructed in the following
mannner : — a is a hollow spindle or tube, at the end of which

XEROtfjLtTTICAL SOCIETY

is fixed a cross-socket b, with two arms. Sliding on the
spindle loosely is a similar socket, c. Into the ferrules of
these two pairs of sockets, taper flexible wands, d d, are
thrust ; these are shaped like billiard cues, and made of light
elastic wood. From the extremities of these to near one-third
the distance towards the centre a piece of fabric, ee, is sewn
between them. A light iron rod passes through the hollow
spindle, having a short cross arm at the outer end. Two
return rods from this, afford the means of compression to a
spiral spring f, surrounding the spindle, and resting on the
sliding socket c. At the lower end of the spindle there is a
cross-handle g , tapped to receive the screwed end of the inner
rod. By turning this handle the spring is compressed, forces
down the lower sliding socket, and of course gives any
required tension to the fabric connecting the rods or arms of
the screw. In this condition the four arms and planes of the
fabric coincide with the axis, but if this is set in rotation, the
two lower arms and socket being free thereon, are forced
back by the resistance of the air, giving an inclined position
to the fabric of the proper form for an aerial screw, with a
somewhat hollow face or expanding pitch, which can be
exactly determined by the tension given to the spring ; if
this is slack the pitch will be a fine one, and when screwed
hard up the lower socket will yield but little, and a coarse
pitch be obtained.

As the rods twist or deviate from each other, of course the
connecting distances between them become greater at the
extremities than near the centre. This is compensated for —
1st, by leaving the middle as an open space ; 2nd, by having
the fabric loose at the extremity, so as to meet the coarsest
pitch required ; and 3rd, the rods being properly elastic at
the ends, yield so as to stretch the fabric uniformly in fine
pitches, giving the blade of the screw a taper form, which is
not an objectionable one, but the reverse.

6f OftBAT BRITAIN.

iTie grfeat advantage of this self-compensating aerial
screw is its portability. The rods may be pulled out of the
sockets, and rolled up together with the fabric as one piece
in a compact form.

There is a peculiar feature connected with the working of
this Society to which it may be as well to allude, viz., its
apparent inactivity.

The work which is surely being accomplished is effected
under a variety of conditions by private individuals, but
almost always under circumstances of discouragement within
the experimenter’s private circle.

In these cases the moral support of the Society is consider¬
able. The Council feel that of theory we have had almost
enough, and that however much the publication of the Papers
read at the General Meetings may have cleared up some of the
apparently insurmountable difficulties attending the subject,
the continual expression of opinion is liable to become rather
wearisome.

We now require and look for facts, and for these we would
wait before 'we call upon members to discuss them.

The Council perceive that those of the members who are
not actually engaged in experiments perfectly acquiesce in
this view by the patience with which they wait the very few
Public Meetings of the Society.

It is not, however, in these Meetings that the real business
of the Society is effected. The Secretary has a large
correspondence, and the calls upon his time in interviews,
both at home and abroad, are more than could be expected
from any one less interested in the subject.

It is the knowledge of this which induces a few members
of the Council to render all possible aid by meeting for
(consultation and in furtherance of the attainment of results.

AERONAT7TIOAX SOCIETY

Dr. W. Smyth wishes in this number to make the
following remarks relative to a Paper read by him and printed
in the Second Annual Report. He feels it the more necessary
because of his statement having been quoted by various
authors. “ After reflection upon the experiments performed
by me in dividing the nerves of the wings of pigeons, I am
of opinion that they were inadequate to determine whether
the pigeon could fly or not with all sensation severed. The
experiments were hastily performed for a coming Meeting
of the Society, and I judged it to be as reported at the time,
but as the experiments are being quoted by others I desire
their actual value to be correctly known."

OF GREAT BRITAIN.

MEMBERS.

Alexander, A., C.E., 13, Cyclops Steel and Iron Works, Sheffield;
of the Council

Arbothnot, H. Gough, 40, Prince’s Gate, s.w.

Argyll, His Grace the Duke of ; President of the Council
Armour, James, C.E., Gateshead
Ashbury, J ames, 66, Grosvenor Square, w.

Ballard, Stephen, C.E., Colwall, Great Malvern
Barber, William, 9, “The Boltons,” Kensington, w.

Baring, Colonel, 36, Wilton Place, s.w.

Barnett, E. W., 25, Lancaster Gate, w.

Barrett, Frederic, Langley House, Grove Lane, Camberwell, S.E.
Baxter, Richard, F.R.G.S., 19, Leinster Gardens, w.

Beadon, Captain R.N., Creechbarrow, Taunton

Bennett, T. J., 20, Little Clarendon Street, Oxford

Borthwick, Lord, 35, Hertford Street, May Fair

Bourne, John Fred., C.E., Louth, and Civil Service Club

Bourne, Edwin, 3, Stafford Street, Wellington, Salop

Bovill, William Edward, 22, James Street, Buckingham Gate, s.w.

Bowden, A. J., 41, Lamb’s Conduit Street

Bowles, Thomas G., 88, St. James’s Street, s.w.

Breabey, Fred. W., Maidenstone Hill, Blackheath ; of the Council,
and Honorary Secretary

Bright, Sir Charles Tiltston, F.R.A.S., Lancaster Gate ; of the
Council

Brooke, Charles, M.A., F.R.S., 16, Fitzroy Square; of the Council

Brooks, Maurice, 10, York Terrace, Regent's Park

Brown, Rev. J. T., M.A., 47, Clifden Road, Lower Clapton, E.

Brown, David Stephens, Braywick House, Green Lanes, Stoke
Newington

AERONAUTICAL SOCIETY

Browning, John, F.R.A.S., 111, Minories; of the Council
Brcnton, N. W., 116, Belsize Park Gardens, n.w.

Burnaby, Captain, Royal Horse Guards

Bcrrell, Edwabd, The Hermitage, 7, Melina Place, St. John’s Wood
Burton, Rev. Roger Taylor, M.A., Lexden Villa, near Colchester
Butler, William Fred., C.E., 5, Cannon Row, s.w.

Chaplin, James C., 12, Craven Hill, Hyde Park
Childs, Thomas, Inver House, Chiswick

Clare, Walter F., Engineer, 2, Agnes Cottages, Elm Grove,
Hammersmith

Clarke, Charles, 1, Coburg Place, Bays water Road
Crestadobo, Dr., Free Libraries, Manchester
Dawson, G. J. Crosbie, 7, Queen Square, St. James’s Park
Deobuz, E., Seetarampore Colleries, Raneegunge, Lower Bengal, India
Delane, John T., 16, Serjeants’ Inn, Fleet Street
De Villeneuve, Dr., 13, Faubourg Montmartre, Paris
Diamond, Hugh W., M.D., F.S.A., Twickenham House ; of the Council
Duff erin, Earl of, 8, Grosvenor Square ; Vice-President of the
Council

Fairbairn, Sir William, Bart., LL.D., F.R.S., Manchester
Gabbtang, James, Bank-top Foundry, Blackburn
Glaisheb, James, F.R.S., F.R.A.S., &c., Blackheath ; of the Council
Greenfield, Captain J. Tyndall, 17th Brigade R.A.

Gbketham, Thomas, 68, Lincoln’s Inn Fields

Gbosvenqb, Lord Richard, M.P., F.R.G.C., 76, Brook Street, w. ;

Vice-President of the Council
Haghe, A., Fern Lodge, Stockwell Green
Hall, George Samuel, Springfield House, Acton, w.

Hammant, W., 32, Bouverie Street, Fleet Street

Habrison, A. Stewart, 133, Upper Thames Street

Habte, Richard, 2, Devonshire Terrace, Notting Hill

Hay, Rear-Admiral Lord John, 149, Piccadilly; of the Council

Hodges, F., Leicester

Holland, Robert, Stanmore, Middlesex

Howell, Charles Augustus, C.E., F.S.A., Northend Grove, Northend,

t “

Fulham

0* GKKAT BRITAIN,

Hutchins, Henry Edward. Tetney House, near Grimaby, Lincolnshire
Ingall, W. T. F. Mm Greenhithe, Kent

Jay, R. C., 54, Alexandra Road, Cambridge Garden*, Kilbum, w.

Jennings, William, F.R.G.S., 13, Victoria Street

Kitson, James, Elmete Hall. Leeds

Krueger, W. G., Downeville, Sierra County, California

Latham, Baldwin, C.E., 7. Westminster Chambers

Le Feuvre, Wm. H., C.E., F.R.G.S., St. Antholin’s Chambers,

26, Budge Row, Cannon Street, E-C. ; of the Council
Lindsay, Lord, 47, Brook Street, w.

Londonderry, the Marquis of, Holdemesse House, Park Lane
Longridge, James A., C.E., 3, Westminster Chambers
Ludeke, J. Ernst F., 15, Wilmot Place, N.w.

Macdonald, Colonel, Assistant Adjutant-General, Dover
Marriott, Frederick, San Francisco, California
Matthews, Edwin, 68, Lincoln’s Inn Fields
Maxwell, Captain R. J., Army and Navy Club, s.w.

Michaels, J. Porter, Christinen Gasse, No. 4, Kolowratring, Vienna

Moilliet, J. Keir, Bishop’s Frome, Bromyard

Morrieson, Colonel R., Oriental Club

Moy, Thomas, 1, Cliflnrd’s Inn, and 37, Farringdon Street

Mulliner, ft; 59, Great Charlotte Street, Liverpool

Murray, Captain R.N., Murraythwaite, Ecclefechan, N.B,

Nees, Christopher, Telegraph Director, Elsinore, Denmark

Newman, Frederick, C.E., 51, Belsize Road

Norman, J. Musgeove, 15, Old Jewry Chambers

Ohren, Magnus, Lower Sydenham ; of the Council

Osler, Abraham Follett, F.R.S., Birmingham

Perigal, Henry, Jun., 9, North Crescent, Bedford Square

Phillips, W. H., Cemetery Road, Nunhead

Procter, J., Old Castle Buildings, Preeson's Row, Liverpool

Reeves, Thomas, 16, Burton Street, Pimlico

Risley, J. B., C.E., Brondeg, Ferryside, South Wales

Roberts, Major H. C., 48, Hereford Road, Bayswater

Rumble, E. L., A.S.E., 12, Maismore Square

Rumble, Fred. Ireland, 9, Bridge Terrace, Harrow Road

AERONAUTICAL SOCIETY.

Satrustequi, Don Joaquin Marcos de, Consul General de Espafia,
21, Billiter Street

Senegal, P., 95, High Street, Kensington
Shill, RiCHArD E., 37, Farringdon Street

Siemens, C. W., C.E., F.R.S., 3, Great George Street, Westminster;
of the Council

Spencer, Charles, Dungannon Cottage, Knightabridge Barracks
Strinofellow, John, Chard, Somerset

Sutherland, His Grace the Duke of ; Vice-President of the Council
Sztrma, The Rev. W. S. Sach, St. Augustine’s College, Canteroury
Tolme, J. H., C.E., 9, Victoria Street, Westminster
Tract, The Honourable Henry Hanburt, Gregynog Newtown, Mont¬
gomeryshire

Walker, Thomas, 24, Oxford Street, Birmingham
Wenham, F. H., C. E., F. R. M. S., Padnall Hall, Chadwell, Essex;
of the Council

Wright, Henry, Stafford House, St. James’; of the Council
Yorke, Pierce Wynne, Dyflryn Aled, Abergele
YOUNG, E. W., C.E., 8, New Street, Spring Gardens

PRESENTED BY THE COMMISSIONERS

THE FOLLOWING

SPECIFICATIONS OF PATENTS.

Date. No. Subject. Patentee.

1872 411 An Aerial Machine . D. S. Brown

„ 821 A new or improved Balloon Locomo- Matthew Augustus

tive, or Navigable Balloon . ) TouL

„ 3076 A new system of manageable Balloon ) j> pt;gte

called Duthu’s system, applicable / Duthu
to the management of Balloons ... )

(Bigbtl) f. mural Report

OF THE

AERONAUTICAL SOCIETY

GREAT BRITAIN.

IFOIR THE NT EAR 1873.

PRINTED BT

HENRY S. RICHARDSON,

GBKENWIOH.

He \irielin-eil noil pii iih'il photol Illin off net for
I’ktk.k Mckkay Hill (Publishers) Ltd.

7:5 sloank Avenue
London s.\V.:5
1 !)5B

Hu per minx inn of the Roi/ol Aeronautical 'iorielii

M A I > K A.\l> I’ll! NTKI> IN' till It AT lililTAIN IIV
H. It. 1111. 1. MAN .V SONS I.TII.. HtoMK

THE

AERONAUTICAL SOCIETY OF GREAT BRITAIN.

President,

HIS GRACE THE DUKE OF ARGYLL, K T.
Utcf-IDrcatljcnts,

HIS GRACE THE DUKE OF SUTHERLAND.
RIGHT HON. THE EARL OF DUFFERIN.

LORD RICHARD. GROSVENOR, M.P.

f^onorarg Secretary,

FRED. W. BREAREY, Esq.

f^onorarg Solicitors,

Messrs. MATTHEWS & GREETHAM, 26, Bedford Row, w.o.

Council,

A. ALEXANDER, Esq., C.E., M.A., Sheffield.

FRED. W. BREAREY, Esq., Maidenstone Hill, Blaekheath, S.E.
Sir CHAS. T. BRIGHT, F.R.A.S., 26, Duke St., Westminster, S W.
CHARLES BROOKE, Esq., M.A., F.R.S., 16, Fitzroy Square, w.
JOHN BROWNING, Esq., F.R.A.S., F. R.M.S., 111, Minories, and
S3, Strand.

HUGH W. DIAMOND, Esq., M.D., F.S.A., Twickenham.
JAMES GLAISHER, Esq., F.R.S., F R.A.S., Blaekheath.
Rear-Admiral Lord JOHN HAY, C.B., 149, Piccadilly.

W. H LE FEUVRE, Esq., C.E., F.R.G.S., 28, Brunswick Gardens, w.
MAGNUS OHREN, Esq., A.I.C.E., F.C.S., Lower Sydenham, s.E.
Lord LINDSAY, 47, Brook Street, w.

F. H. WENHAM, Esq., C.E., Y.P.R.M.S., Padnall Hall, Chad well,.

Essex.

HENRY WRIGHT, Esq., Stafford House, St. James’.

WITH POWLR TO ADD TO THIIB NVMBFR.

Member’s Subscription, £l.ls. per annum, c’atii g fr< n. ti e dry of Election.

Ladies may become Associates upon the same terms.

(STnjFjtfj Annual

OF THE

AERONAUTICAL SOCIETY OF GREAT BRITAIN,

FOR THE YEAR 1873,

Containing an Account of the Proceedings, and a Selection from the
Papers and Communications received by the Society during the
year, with concluding Remarks upon the present state of the
Science.

The Annual General Meeting of Members of this
Society was held in the Rooms of the Society of Arts, on
Monday Evening, the 30th of June, 1873. Mr. Jamks
Glaisher, F.R S., presided. Several models and specimens
of apparatus were on the tables, and were exhibited in the
course of the evening.

The Chairman, in commencing the business of the
Meeting, said: Ladies and Gentlemen, — We meet again
hopefully, as we have met on previous occasions. We have
to speak to-night, I think, of some progress; our progress
has been for some years very slow indeed. 'Whether it has
been much accelerated during the past yrar I cannot say, but
still I think a decided improvement has been effected. It
has been a year distinguished from previous years by experi¬
ments, and it is to experiments we must look for any ultimate
success that may attend our efforts. As I have before
said, those experiments that are essentially necessary and
strictly applicable to aeronautical navigatiou have this great

AEEOIf Atm CAL SOCIETY

advantage — that, even should we not succeed in our hopes,
our knowledge is increased in the direction required, and in
a direction which may be useful in providing for the wants
i>{ man Therefore I have urged the continuance of these
experiments, because good must follow from them though the
ultimate object may or may not be attained.

Perhaps I may be permitted to say a few words on some
of the attempts that were made last year. In the order of
time that of M. Dupuy tie, Lame should be first noticed.
M. de Lome attempts to cause a balloon to deviate from the
direction in which the wind blows, and his invention is one
to which some attention should be paid. Two conditions, he
said, must be complied with in order to achieve his purpose.
The first is the permanence of form of balloon ; and the
second is that the least resistance should be in a direction
parallel to the propelling force. The weight of the balloon
in which he made the experiment was about a ton. -and
three-quarters, but, when everything was ready, the weight
was increased to four tQns. The screw was worked by manual
labour. M. de Lome has made experimental trips with this
balloon ; and he states as an absolute fact that he did Cause a
deviation from the normal direction in which the wind blew of
as much as twelve degrees on the one side and twelve on the
other. That is a gnat achievement. What a blessing it
would have been if such an invention had been in operation
at the siege of Paris! We feel grateful that a power did
exist to give us news from the interior of the city ; but if this
discovery had then been made we could have sent news in as
well as got intelligence out. M de Lome employed seven
or eight men to work the screw. A small engine would have
done better and would never tire. However, in what has
been done, there is evidence of a distinct advance.

The second invention I have got to mention is that of
Paul Hanlein, who has made a gas engine for balloon

OF GREAT BRITAIN.

propulsion, — to propel the balloon against the wind. On the
construction of this engine, and also of the balloon, we have
had a good deal of correspondence ; and we were told in
reply to our enquiries, that both had been tried, and been
started from a given place anrl brought back again. The
Aeronautical Society of Vienna have, however, dispensed
with the services of Mr Hanlein, and we have been unable to
ascertain the reasons. Mr. Mov, who has just returned,
could not tell me. The Vienna Society have constructed a
balloon for themselves at an expense of £1200.. and they
have now taken advantage of what two of our members have
done, and have ordered a four-horse power engine which I am
told is to be the lightest engine in proportion to its power ever
yet constructed. May it be so. became if it should be so we
shall have made a great and good step m the direction in which
we are working. With regard to balloon propulsion, for my
own part knowing how completely at the mercy of wind
I Lave been in balloons, I can hardly think any power can.,
control them. They may vary a little right or left, but the
wind must always have power over a balloon, especially if it
is a large one. I have had enough experience to feel certain
of that. We have great satisfaction in knowing that the
long-desired engine has been obtained, and that at length
we shall be enabled to aid the balloon by an engine of
lightness, power, and safety. I was asked In Mr. Brearey
whether I would go into a balloon with one of those engines.
I said that if the bottom of the balloon were closed, so that
the gas could not come out. I would go. But for purposes
of experiment six feet from the ground would be quite as
effectual as sixty.

Mr. Bue\uey remarked that the engine was intended
to aid in ascent and descent only.

The Chaikma.v ; Well, let us do everything from the
beginning. Ascent and descent is all we can try at the

AERONAUTICAL SOCIETY

present moment. These Gentlemen (Messrs. Moy and Shill),
members of our Society, who have often spoken here and
given us the benefit of their labours and attention, have now
taken out a patent for this engine ; and all I can say is, God
speed them, and may they be successful (cheers). I will not
longer occupy your attention, because there are several
papers to be read. I can only say for ray own part that the
fact that the results of investigation in one direction should
have produced an engine of this kind, shows that the
application of our exertions is not at all limited by the
objects for which those exertions are intended. Here is a
certain object attained, Herschel, when he examined two
small stars close together, with the view of obtaining the
parallax of the brighter, and found that one went round the
other, left his original object of enquiry while he pursued
the new investigations thus suggested. So these gentlemen,
having started in one course, will now follow that which may
be most beneficial to mankind at large (hear, hear.)

Mr. F. W. Brearky, the lion. Secretary, read a
communication from Mr. Abtimgstai.l, of Manchester,
as folio W8: —

Sib,

The most difficult problem to solve respecting the flight of birds
is the question how does a bird maintain flight without progression, like
the kestrel hawk, &c. ? Even the heavy and slow winged heron must
be able to hover, or it would be utterly impossible for it to alight, as it
does, so gently on its nest and eggs, and dispose of its long shanks. It
must also leave its nest equally as geutle. This totaLly disproves the
common assertion that a large and heavy winged bird is obliged to run
before it can get on the wing, or else start from some eminence. The
fact is that no bird could alight on a particular bough or spot without
some degree of hovering. But the difficulty of explaining the theory of
hovering becomes very great when we know that the muscles which
depress the wings of a bird are far stronger than those which elevate
them, and also the muscles that depress the back edges of the wings are
stronger than their opposing ones ; yet the upstroke is as quick as the

The planes of the wings are at right angles with the wand w, excepting the little raising of the back edges (as mentioned)

just to catch the air at the beginning of the down-stroke.

OF GREAT BRITAIN,

1«

A.ER.OSTA.'CTICAX SOCIETY

downstroke. My decided opinion is that true flight requires the vibrations
to be equal like a musical tone, and that the wing is raised by the reaction
of its back edge against the air, and of course the reaction of the air
against it.

To illustrate hovering, in some measure, I made the following
experiment (see diayramj : — aa. the wings, that is the front or thick
edges of them ; cc the back or thin edges of them ; w a wand or stick
about the size and length of a common 4 -inch walking stick, one end of
which is attached to the wings at B, and the other to the centre D, that
moves on the pivots pp, so that no support can be given to the artificial
bird but the air ; H is a handle like the handle of a common corkscrew ;
E represents the body of the bird, and is made from very thick cardboard ;
it is more for ornament, or to show the direction of flight, than for any
real use. The expanse of the wings is lift. 9in. from tip to tip ; their
breadth 12in. ; the weight of the bird and wings 8oz., that is without the
handle and wand.

Now it will be evident that if the handle H be grasped, and a motion
given to it so as to tv ist the wand w backwards and forwards, it will cause
the wings to vibrate like the balance-whpel of a timepiece. Now if the
wand w be placed at an angle of 45'1 with the horizon, then the plane of
the arc of vibration of the wings will be at 45“ with the horizon , there¬
fore the wings will not strike directly downward, but at an angle of 45u,
and rise in the same angle. The wings are fixed with their thin edges co
slightly raised above the plane of the arc of vibration, so that at the
beginning of the downstroke the air may catch underneath the surface of
the wing and continue to bend its back edge upwards until the termination
of the downstroke. Now when the wing rises, its back edge reacts down¬
wards, so this stored-up power is returned, and ' continues the buoyancy
of the artificial bird during the upstroke without any motive power being
expended. It will be seen in this experiment that the wings do not act
independent of each other like birds’ wings, but as though they were at
each end of a balance. From this it might be supposed that constant
buoyancy is only maintained because one is in full power whilst the other
is ascending. That such is not the case is proved by stripping the
covering off one wing and retaining the “ bare poles ” or skeieton merely
to balance the other, yet this one wing maintains constant buoyancy,
but it requires much more dexterous manipulation to produce uniform
pulsations as the balance of resistance is disturbed.

In addition to the reaction of the back vibration in raising the wing,
the elasticity of the wing-stems aa I believe assist the flight, as they axe

OT GREAT BRITAIN.

bent in the down stroke and return to their neutral position during the
upstroke. Perhaps the elastic torsion of the rod w may play a part in
producing constant buoyancy. After all there is something at prestnt
inexplicable about the action of this apparent toy ; but one thing is
certain that, if the model be well made and uicely handled, it will hover
beautifully at the end of the wand w with a silent gentle and equable
motion, as the poet would say, like the soft flutter of an angel's wing.
Certainly very unlike many attempts that are being made to produce
flight by might and main force with their violent and useless flapping,
wafting, skimming, screwing, &c., what may be called trying to fly with
a vengeance without first getting to know, by experiments, the true
theory of flight and the power required.

I may observe that elasticity plays a primary part in the foregoing
experiment, just to prove the existence of a great principle ; but in a
bird’s wings elasticity is only secondary, for ten times better effect is
produced by the beautiful and wonderfully organized play of the muscles,
both of the thorax and the wing itself, which develope the wonders of
flight, and enable first class flyers to fly with very little expenditure of
motive power.

From my numerous experiments and observations I am now
thoroughly convinced that man possesses far greater muscular power
than is requisite for tolerably swift horizontal flight. According to the
principles 1 have laid down isee 5th Annual .Report of the Aeronautical
Society of Great Britain, page 3d), ail that is required in swift
horizontal flight to maintain buoyancy is a very slight and imperceptible
direction of the propelling force of tiie wings upwards ; this I call the
anock OF buoyancy. If the wings propelled quite horizontally, the
bird would soon go to the earth like a military projectile tired horizontally ;
but this slightly oblique action of tiie wings upwards simply prevents
descent beginning, and that, too, by an almost nominal expenditure of
power; but when the bird gradually goes slower the obliquity of the
angle of buoyancy increases and is soon peiceptible, yet the bird may
still continue its horizontal path, but as the progressive speed decreases
then, of course, the resistance of the atmosphere to the body of the bird
also decreases, but the buoyant power required becomes greater until
progressive motion ceases, then the bird must hover to maintain flignt at
the same elevation, but it generally alights on a bough or elevated spot,
for the generality of birds do not like the labour of hovering even for a
few seconds

1 feel confident that my theory of the angle of buoyancy will be of

AERONAUTICAL SOCIETY

vast practical importance to aeronautics, particularly as X could now
produce wings of great propelling power which could be easily and simply
worked by manual power without any complex machinery.

However cheering it may be to think that swift horizontal flight
requires very little power (as far as buoyancy is concerned), yet it must
be remembered that this is only the effect of flight already obtained. To
obtain the cause or primary flight is the great difficulty in Aeronautics.

I am, Sir, your obedient Servant,

To F. W. Brearey, Esq. F. D. Ahtingstall.

Mr. Moy thought few persons would understand the
paper which had been read. He really could not see the
drift of it, though he had paid some attention. The writer
spoke of hovering as being a difficult performance. Mr. Moy
believed the motions of a bird could be explained on
engineering principles, and it was his opinion that if the bird
was not head to wind it could not hover. The writer also
attempted to prove that the power of alighting gently, proved
that no run was necessary at starting, whereas it proved
nothing of the sort; the two movements were very different.
When the bird was coming down its wing acted as a buffer
on the air. The writer then said it was difficult to explain
the theory of hovering. That he did not see. He thought
it very simple. Then the wri.er ran down all attempts to
produce flight by main force. He (Mr. Moy) would however
continue to rely on that until they could do without it.
They had experimented, and he believed they had found out
the true theory of flight, and on that subject he hoped before
another twelve months he would be able to enlighten the
Society, and to show that the true theory of flight had been
found out and patented more than a year. The writer also
stated that he thought man had ample muscular power for
accomplishing flight. In his shop he had got a pair of aerial
screws. and the utmost weight that a man could lift with
them was about 181bs. No man, he believed, would fly by

OP GREAT BRITAIN.

his own muscular power. Machinery, in his opinion, would
do it. He could not compliment Mr. Artingstall on his
paper at all.

The Chairman said they had long since given up the
idea of a man flying by muscular power, and had begun to
devote their attention to machinery. All they wanted to
have was experiment. In his belief experiments, whatever
they might be, would prove useful. He would suggest that
the thanks of the Meeting should be given to Mr. Artingstall
for his paper.

A vote of thanks was accordingly given.

Mr. D. S. Brown read a paper on the Aeroplane;
embracing its construction, stability, and means of propulsion.
Mr. Brown, in the course, introduced several models and
various lightly constructed apparatus illustrative of his
remarks.

THE AEROPLANE.

It is more than half a century since Sir George Cayley published the
result of his researches in elucidation of the problem of Aerial Navigation
by mechanical means, which was followed, several years afterwards, by
the celebrated project of Mr. Henson, and since then has also appeared
a valuable contribution by Mr. Wenham. Yet, up to the present time,
no steps have been taken to give to any of these discoveries a practical
value. This is much to be regretted, as it represents so much time
unnecessarily lost, and has probably delayed the realization of the most
important means of locomotion for more than one generation. Having
myself devoted a great deal of time and attention to the Subject under
every aspect which it has assumed, I will state, as briefly as possible,
what I consider the essential conditions to be for achieving success by
the aeroplane principle of support. And first, as regards the

Construction.

The membrane of the plane should be as smooth and tight as that
of a drum, which may be best effected by fixing it on the frame when in
a moist state, or constructing it in parts, or of indiarubber ; and if also
made double-walled it would serve as a condenser for recovering the

AERONAUTICAL BOCIJCTY

waste steam when steam is used as a motor, which would he necessary
on a long voyage. The forward edge of the plane should terminate in
as acute an angle as possible ; but I have ascertained by experiment
that this is not so necessary with respect to the posterior one in air, as
is found to be the case in water, on account of the much greater velocity
of the former in closing a vacuum. This is so far fortunate, as it admits
of the cleaving angle being made more acute ; and in the construction
of balloons the matter would be of still greater importance. It is
generally thought that, on account of the strain to which such a
structure as an aeroplane would be subject, its size must be very limited.
But this is only true when the greater part of the weight is concentrated
at one point. If the load be equally distributed over its surface, the
plane will be supported by the air with as little strain as a plank is
on water. Still, it might be very desirable that the framework should
be elastic, to prevent fracture and diminish concussion in making
a descent. It has been remarked “that if no one had ever seen a bird,
nobody would believe in the possibility of flying.” But not less
wonderful is the graceful way which the bird folds its wings close to its
body when not in use, so as to form no incumbrance in walking ; as well
as the exquisite manner in which the feathers are arranged, that even in
stemming a gale not one is ruffled or displaced. The aeroplane, however,
by reason of its more regular form, affords still greater facilities for
rendering it portable, by hinges, joints, sliding tubes, Slc.

Position

The Aeroplane should not be inclined to its path of motion, but its
surface form a direct line with it. There will then be no resistance
excepting from friction and the forward edge of the frame. The plane
can be kept at the same elevation by slightly directing its course
upwards, sufficient to compensate for any fall which may take place.
Mr. Wenhain stated that a rise of 1 in 30 would do, provided the
progressive motion were 30 miles per hour, and the plane loaded to the
extent of lib. to the square foot. Without such rise in its path it would
fall at the rate of about one mile an hour, or, without the horizontal
motion, at the rate of 15 miles per hour. The failure of Mr. Henson’s
efforts is, I think, partly to be ascribed to the use of an inclined plane,
for when only one is employed there must be a difficulty in maintaining
the required inclination, and at a high velocity the resistance from the
surface would have to be met by great force. The following diagrams
will assist in illustrating what I have said : —

Of GEEAT SUTAISr. 16

Fig. 1 represents the side edge of a plane, the path of motion of
which (a) rises slightly. Fig. 2 is a similar view of another plane, the
path of motion of which (b) is horizontal, and the plane inclined to it.

Stability.

This is conferred by motion on bodies in a most striking manner, as
tops, hoops, arrows, and many other things illustrate, and the aeroplane
will be found to form no exception to the rule. At the same time the
importance of properly adjusting the centre of gravity must not be
overlooked, and which should be as much below the level of the plane as
possible. I have, however, been successful in greatly increasing the
stability by employing two planes ; one placed before the other at some
distance, and both connected by a rod. c and d, Fig. 3, represent such
planes, and t the connecting-rod.

•1EB0WAUTICAL SOCIETY

These, on receiving a horizontal motion, will glide steadily along
like a bird skimming ; and the arrangement admits of the planes being
inclined, should such a position be at any time found advantageous.
A self-acting rudder can also be made, by placing a ball free to move on
the plane. Any faulty inclination, such as pitching, would then be
corrected by the motion of the ball being communicated to the rudder
by a string. And the principle admits of many modifications, such as
allowing a liquid to run off either end of the plane, which may be
faultily inclined ; causing a weight to move backwards and forwards by
means of a spring set in motion by the inclination, &c. , &c.

Propellers.

Those having an oblique action are best adapted for aerial
propulsion, because they are able to overtake the wind or receding
current of air caused by the progressive motion of the aeroplane with a
velocity as much slower than the wind or such receding current as may
be the ratio of their obliquity. It is thus that a bird is able to propel
itself so rapidly with a comparatively very slow motion of its wings.
For if the obliquity of the stroke be as 1 to 10, every inch which the air
is pressed down by the wing will force the bird forward 10 inches. It is
precisely the reversed action of a wedge, or similar to a sail set to a side
wind, and any one may obtain a practical example of it by observing
the slanting manner in which a piece of tin or any plane body sinks in
water. As may be expected, the thrust is diminished in proportion to
the obliquity of the stroke, but it is compensated for by the slowness of
the motion, so that the question of power is not involved. Should
a screw be employed, it must therefore be at a very great pitch, although
I think that reciprocating planes, acting like the wings of birds or tails
of fishes, are preferable. The rocket principle of propelling, on account
of its extreme lightness and simplicity, recommends itself. But air
discharged from a bellows at so low a pressure as half-a-pound to the
inch, has a velocity of 1 47ft. per second, although by heating it to a high
temperature as it escapes the useful effect may be more than doubled.
I have some important improvements to suggest as to economizing
■team when used for propulsion in this way.

Motors.

Gravity is the most easy force to employ, and large birds always
avail themselves of it when they can to obtain their initial velocity, by
starting from some elevated spot. “About 60 years ago,” according to

OF GREAT BRITAIN.

Sir George Cayley, “ many experiments on a large scale were made by
this means, some of the aerial vehicles having 300 to 400ft. of canvas,
extended on masts and braced by rigging ; and a surface of 54 sq. feet,
weighing lllbs., was found to support 1261bs. in its waft. These
trials proved, in a most decided manner, that perfect stability and
guidance were attainable. For instance, it was proved that a man
placing himself on a machine of proper dimensions for his weight, at the
top of a mountain, say one mile above the level of the plain below,
might, in calm weather, with steadiness and security, proceed through
the air to any place he might choose to steer, about 8 miles in a
horizontal direction. Of course the line of flight would be in a continued
descent of 1 in 8, gravity being the only cause of the motion of the
machine.” , Impetus, or communicated motion, where the motor is
separated from the body moved, is often necessary to obtain initial
velocity ; and I think this will be more requisite with respect to the
aeroplane than any other vehicle. The motion of all projectiles, as well
as that of the aerial top, is due entirely to this source. Next in
simplicity is spring power ; and lightly as it may be regarded, it is by
this that the most striking results have as yet been obtained in
mechanical flying. True, the machines were only toys, but they carried
their motors, although the power was used in the most wasteful manner,
so much so, that perhaps no bird of the same weight ever expended so
much in the same time. I find by experiment that about 151bs. of
indiarubber cord, stretched to seven times its length, will, in returning
to its normal state, yield a power equal to one horse for a minute. It
should be placed in the tubular framework of the aeroplane, tor it is
dangerous to handle when so stretched. The same result might be
obtained by placing there instead, 61bs. of solid carbonic acid, which,
without artificial heat, will pass into a gaseous form, and so could be
made to work an engine like steam. The objection to spring power is
its short duration, but a confined fluid may be made to act as a spring
by alternately heating and cooling it, and the force would be thus
rendered continuous.

I now come to consider a most important power, namely, manual
power, and it will greatly curtail what I have to say, if I state in the
first instance that in estimating the power necessary for flight, one of
these mistakes so peculiar to the science of Aeronautics is almost
invariably made. The one in question arises from supposing that force
is necessary to sustain a body in the air as well as to propel it. Now,
force is certainly required for propelling, for it implies motion under

AERONAUTICAL SOCIETY

resistance. But, theoretically speaking, no power is necessary to support
a body, under any circumstances, where no elevation of it takes place.
In practice, however, it may amount to almost anything or nothing,
according to the conditions observed. In the case if the toys alluded to,
which were sustained in one place by the continuous lotion of screw
propellers, it was enormous. Small bird. ;,m» insects, on the other hand,
as I explained in a former paper diminish it ho < fraction by intermittent
motion ; but with respect to large bird;- where blip support is merely the
effect or consequence of propelling, no allowance whatever need be made
for it. Now, a fair comparison between bln locomotive performances of
animals in the air with those in the gmuno will 'how i result vastly
in favour of the former. Lt-is therefore not nnreasonabh to assume that
a man who can propel himself well upon vHocipem. or t.oe. ground,
would do so still better with a suitabh machine in th* nr. It so
happens that the position in which he can exert the greatest amount of
muscular power offers also most resistance to the air, and I need scarcely
say that such resistance is very different in flying to what, it is in
v’alking. It would therefore be necessary for him to work in a narrow
compartment, having its front brought to a very acute angle. This
would diminish the resistance to about a quarter, and two or three men
working in it in a line would reduce the proportion much more.

I will pass the giant motor, steam, by observing that if the weight
of the steam engine, or rather steam boiler, ever formed an obstacle to
its use for aerial navigation, it has long since been removed by the
Society’s prize engine, which proved that everything could be brought
within 301bs. per horse power. To say nothing of gas engines, of the
explosive and non-explosive kind, where no boilers are necessary, as well
as electric ones.

In conclusion, I would suggest that experiments should be made
with the aeroplane on a large scale, with a view of ascertaining its
locomotive value, as compared with that of a wheel carriage of the same
weight on the ground. The initial velocity could be given by a swing or
by launching it from a balloon, and the motion afterwards continued by
gravity, a spring, manual power, or any other motor that might be
advisable to employ. These would solve a number of valuable and
interesting problems, such as, whether a man possesses sufficient power
for flight, and if not whether flight is practicable at present by
mechanical means at all. Even if it should be found that it requires
twice as much force as locomotion on the ground, it would not be less
economical, provided the journey were made in half the time. In

OF GREAT BRITAIN.

forming an opinion of the probable success of steam, it should be borne
in mind that it has only to exhibit the same superiority over animal
power in the air that it has always done elsewhere. The large
locomotives formerly employed on the Great Western Railway were
capable of working up to 1 0Q& -herse-power, although they only weighed
35 tons, including the water and fuel, and the tender 17 tons ; which
shows a power, in proportion to weight, more than four times as great
as that of a horse. To insure as much safety as possible, the experiments
could be made above water. And on the subject of safety, I may
remark that in locomotion where machinery is employed, nearly all
accidents happen by collisions. These are more likely to occur on
railways where travelling is on the same line, or at sea where it is on
the same plane, than in the air, which is a portion of a sphere, where a
thousand aeroplanes may cross each other’s paths, at different elevations,
and without coming into contact. Even in case of an accident to the
engine, the progressive motion of the aeroplane could be continued by
gravity until it reached the earth, which it would probably do in a gentle
manner as birds are seen to alight. Besides which, springs could be
also employed to break the fall. Judging from the theory of M. de Lucy,
which is corroborated by the experiments made by Sir George Cayley, as
regards the proportion of weight to surface, a plane of 24ft. by 6ft. would
be more than sufficient to support a man. This could be propelled with
great steadiness by a screw, but much more effectively by the plane
itself if its sides were made to move up and down from joints at the
centre, like the wings of a bird, in which case the anterior edge of the
plane should be rigid, and the other part yielding or elastic. At a
distance of not less than 20ft. before or behind the aeroplane should be
carried another smaller plane to serve as a tail and rudder, and which
should also have affixed to it a vertical one, and the whole moved by an
arm turning on a universal joint. The simultaneous elevation of this
with the wings and a horizontal fish-tail propeller behind (should there
be one), would cause the machine to descend as steadily as a shuttlecock,
although too rapidly unless it had a horizontal motion as well, or the
aeroplane were made to revolve or to move quickly backwards and
forwards. I think, however, that superposed planes are much better.
These could be arranged in two groups or sets, each group consisting say
of 12 planes 12ft. long and 1ft. broad each, put one above another at
1 2in. apart ; and one group placed before the other at a distance of
about 20ft., but connected by a beam. Such an arrangement would
combine the greatest sustaining power with compactness and stability.

AERONAUTICAL SOCIETY

Aeroplanes may also be wholly made of any airtight membrane, and
rendered rigid and even buoyant by inflation.

The Chairman said they must thank any member of
the Society who had devoted so much thought and time as
Mr. Brown must have given, and they ought to give their
thanks to him for having exerted so much patient labour.
He had no doubt Mr. Brown would be willing to give further
information to those who required it, at the end of the
Meeting.

A vote of thanks was passed to Mr. Brown.

Mr. F. W. Brearey announced that Mr. Bennett had
been engaged in experiments, and would exhibit the results.

Mr. Bennett introduced an Aeroplane invented by a
Frenchman, to be worked by a screw' by motive power
derived from elastic springs. The great feature about it was
the balancing tail, which was regulated by the oscillating
motion of a weight. The apparatus was throw'n up in the
air, and flew writh good effect across the room.

Thanks were given to Mr. Bennett for his services.

Mr. Mot was then called upon to describe his engine,
which was fixed on a table in front of the Chairman, and
occupied less than a cubic foot of space. He began by
stating that lOOlbs. pressure could be got up in a minute and
three-quarters. It would, however, be better that the
Meeting should see the engine at work before he described it.

Mr. Shill lighted two gas, jets in communication with
the machine, and within two minutes the pressure was seen
by the gauge to be lOOlbs. to the inch. The engine was
then started at about 800 revolutions per minute. It was
stated that there was about half-a-pint of water in the boiler,
and that the average consumption was about six pints per
hour.

OF GREAT BRITAIN.

Mr. Moy said he would first make a few remarks on his
visit to Vienna. At the Meeting of the Aeronautical Society
there, the language spoken was German, which he was sorry
he did not understand ; but they had a large model balloon
filled with gas, and fitted with an ingenious mode of stiffening.
Mr. Ofenheim intended to use the same process in his
elongated balloon; but he felt bound to tell him that his
engine would never drive the balloon against the wind, and
Mr. Ofenheim said he did not expect it would. He then
told Mr. Ofenheim he would give him an engine which
would not weigh more than 40lbs., and which would give
the actual power of four horses. There was a small machine
in the room at Vienna, which was driven round the room
by the screw working in the air.

He must now say a few words about his own engine.
By reference to a drawing behind him they would see how
the water circulated. If they could see it actually they
would be astonished at the rapidity with which the water
circulated. It went at such a rapid rate that no sediment
lodged in the tube. The water, passing rapidly over tbe
heated metal, extracted all the heat from it, and kept the
tube cool. By this means a large quantity of steam was
generated. The engine had a stroke of two inches, and
one-and-a-half inch piston, and it was using six-and-a-half
times as much steam as they ever intended it to do, because
they had removed the cut-off valve, and therefore they were
actually wasting their steam ; and it was now working at
great disadvantage, through the furnaces and tubes not being
enclosed. This engine was of very light weight. They
could make them almost any weight, and for aerial purposes
they could bring the weight down to 71bs. per horse-power.
The engine for Mr. Ofenheim would not occupy one-third of
the space allotted to it, which was one square yard.

Captain Greenfield : Do you mean** /^pbic yard ?

AKKONATTriCAJL BOCimr

Mr. Mot : A square yard. Aa to height we do not
want much. We can work at any reasonable pressure, and
these tubes are practically inexplosive. The engines which
we have made have been tested up to 5001bs. on the
square inch, and they do not require to be worked over 200.
We have not much body to make, and therefore can make it
of great strength. It is very economical in working, because
all the heat that gets in is stored up. There are no long
passages to go through, and when it gets into the cylinder
there is nothing to make the steam condense until its work is
thoroughly done and all the power is got out of it. The
circulation is perfect. Charles Wye Williams had more than
twenty years ago said that whenever engineers designed
boilers capable of rapid circulation they would obtain far
better results than they did at that time.

The Chairman remarked that Mr. Williams had said it
in that very room.

Mr. Mot went on to say that of course when people saw
new things there were plenty of objectors. He would take
two or three classes. One class of objectors said the tubes
would stop up, as if the inventor was not likely himself to
have prepared for such a difficulty, and be likely to see it
first. The objector fancied that the inventor never saw
anything of that. Now it so happened that the tubes did
not stop up. Objectors said they would stop up ; he had
only to say in reply they did not stop up. These tubes
had now been working more than twelve months. They had
been working with common water, though in practice they
meant to use condensed water. Yet the tubes did not stop
up. Another objector said the circulation was so rapid that
the tubes would wear out by circulation, so he expected these*
tubes would get as thin as a piece of paper in a short time;
however, they did not. So he thought bet wet u these two
classes of objectors they had got to tKc right joint. There

OP GREAT BRITAIN.

was another class — the cceteris paribus people — of whom he
would say more presently. Now he had given a hint that
they were making an aerial machine. It was a working
model, and would be 13ft. by 10ft., and 6ft. odd in height.
It would have an effective lifting surface of 60 square feet
always acting on the air. There would be a 4-horse power
engine in it. Some people said this power was not wanted.
He would tell them what he thought about that. When a
boy wanted to learn to swim he began with bladders and
continued until he could swim without them. So it was
with power iu an aerial machine. When they were coming
down power was wanted, and of course power was especially
wanted when they were going up. When the machine got
in motion they did not want much power, and when his
engine was at work in an aerial machine he should reduce
the power by outting off the steam earlier in the stroke until
about one-tenth only of the power was used in rapid motion.
What they wanted was power in starting to obtain speed ;
and power in corning down to control the descent. He
then referred <-o the highly interesting experiments made
by this Society which were reported upon last year.
These »x peri merits ue had analysed, and from the data
thus obtained iie had made a geometrical table, whereby
the lifting power and resistance of aeroplanes at angles
from 90° to 5J, and at speeds varying from 10 miles an hour
to 40 could be calculated. 11c should be happy to give
further explanation to any one who desired information, and
that was ull he had to say that night, except in answer to
any remarks that might be made.

The Chairman said this invention was an important
one, and afforded a good illustration of the remarks he had
made in opening the Meeting. The engine and boiler were
not mere models, but were actually working. The engine
was one possessing great pow6r. He should be glad to know

AERONAUTICAL SOCIETY

whether bn the same principle Mr. Moy could make a large
engine.

Mr. Moy : A large engine would be proportionately
lighter. A 100-horse power engine would not be more than
7O0lbs. weight.

The Chairman remarked that this engine had been
found out through researches for aerial navigation, and from
experiments which had been made from time to time until
success was attained.

Mr. Shill said the engine had been at work twelve
months and nothing had been done to it.

The Chairman : Did you use a condenser ?

Mr. Shill: No; we feed it with ordinary water.

Mr. Moy : With a good condenser the consumption of
Water would be very much less.

Mr. Clare : We have not heard anything as to fuel.
Can you give us the fuel per horse power per hour ?

Mr. Moy : Mr. Burgh estimates lib. of coals per horse
power per hour.

Mr. Clare : But it has only been worked with gas ?

Mr. Moy : We can work with gas, petroleum, or
anything you like. Mr. Ofenheim is going to use gas.

Mr. Clare : But nothing has been used except gas.

Mr. Moy : No.

A Member : I presume in practice this flywheel would
not be used.

Mr. Shill: No.

The Chairman : I must ask you to give your warmest
thanks to Mr. Moy and Mr. Shill. That they should have
produced an engine which will help us to descend gently is a
very great thing indeed. I am sure, in giving those thanks,,
we all wish the aerial machine may be successful. It was
plain that the Austrian Society, by spending £1,200. on a
balloon, considered the balloon was essential to aerial navi-

OF GREAT BRITAIN.

gation. There was no balloon belonging to this Society, so
that they were really depending upon experiment. It was
very likely they would have to proceed step by step, and to
use the balloon as a raising power, and dispense with it by
degrees. With Mr. Moy this result had been accomplished
little by little. So should the Society reduce the use of the
balloon till they could do without it. It was just possible if
they had a balloon of their own they would be independent
of caprice, whim, and chicane ; for, so far as his experience
went, no aeronaut he knew wished to improve the balloon.
That was not the object of the Society. They wanted to
improve, and to do away with the balloon entirely. The
balloon was a tyrant which took you where it would. Some¬
times you came down very agreeably, and sometimes under
very unpleasant circumstances. He felt more struck with that
Meeting than any other they had held before, and he did hope
that when they met again they would be able to say they had
progressed still more. He would now close this Meeting,
but he was sure Mr. Moy and Mr. Shill would be willing to
give any explanation ; and he was convinced they were all
much obliged to them for what they were doing in this
direction. (Cheers.)

The Meeting then separated.

The following Paper communicated by a Member of the
Society could not, from its great length and the number of
diagrams necessary to illustrate it, be read at the General
Meeting.

iBBOlTAtmOAL SOCIETY

WINGS FOR MAN.

JAMES ARMOUR, C.E.

PREFACE.

Ih the short work here prefaced, the Author seeks to determine
approximately the sustaining power of planes disposed in such manner
round the axis of a wheel that, when the wheel is put into rolling
motion upon the ground, the increasing velocity of rotation may
give air pressure to the planes, to float the weight and propel it
on a forward course when floated.

The manner in which the question is treated will show that
the title “Wings for Man” signifies not wings absolute, but wings
in the form of a proposition simply.

Gatbshjlad,

Augutt, 1871.

JAMES ARMOUR.

OF GREAT BRITAIN.

WINGS FOR MAN.

Chapter I.

Ilf Fig. 1 we have 12 planes set round the circumference of a wheel
of 8ft. diameter, and relatively inclined as shown, so as all to radiate
from the topmost point A .

Fig. 1.

We assume these planes to have long lengtL parallel to the axis of
the wheel, and t,o be looked at endwise in the figure, so that their
breadth alone is shown ; and that breadth is assumed to oe 1ft. = ob, to
make the values of the sines and cosines of the angles as they stand in
the Tables represent the area of air displacement in simple relation to
the actual breadth 1 '0 ; and will first treat them as if each measured
only 1x1=1 square foot.

Taking the angles with reference to the horizontal line cd, the areas
of air displacement earthward in the direction X will be represented by
the cosines, and the areas in the direction Y by the sines.

(2) If the wheel, with no motion round its axis, and with the
planes disposed at the angles shown, were free to fall in the direction X,
the area upon which the resistance to air displacement took place, would
be to 12 square feet as the sum of all the cosines, divided by 12 for the
number of angles employed, is to 1 square foot, or nearly as 0 6368 to

AERONAUTICAL SOCIETY

l'O ; which gives 0'6366 x 12 = 7 '6392 square feet projected or cosine
area of displacement.

W ere the wheel, with its planes thus stationary, moved bodily in
the horizontal direction Y, the projected or sine area of displacement
would be similarly 7*6392 square feet ; as in both cases, however, the
rearward planes are variously screened from the air pressure by the
planes in front, the actual resistance would be represented by a less area
uniformly open to the pressure.

It is not necessary here, however, to determine the loss due to the
screening of the planes in the rear, as this loss has reference not to the
angles of inclination, but simply to the position in the wheel.

(3) Supposing the wheel, without either Y or X motion, were to
revolve round its axis, we would have the plane A describing an angle of
90° in its passage from A to h on the arc A eh ; that is, would have it
changing its value as an area of resistance from 0 0 at A to l'O at h ;
and we get the ratio of resistance parallel to fe, to that parallel to Ah,
by dividing the diameter by the half circumference ; thus, with the
diameter equal l'O,

3'1416

= 1-5708 = Aeh,

— ; — . — - = 0-6366 for X to 1 for Y, mean value on the arc, when
Aeh 1-5708 ’ ’

the value Y at h is 1*0 (pars. 14, 32).

(4) If, while the wheel is thus turning on its axis, we move it bodily

in the direction Y, the plane, in the act of making one half-turn ad'h'

round its axis, actually describes the curve aa" of Fig. 2, and this without

Fig. 2.

OP GREAT BRITAIN.

altering the 0’636(5 mean area value of the plane, considered apart from
the greater bed of air support ; because, on the curve cut", the change in
the angle of inclination from 0° at a, to 90° at a", is identical with the
change from 0° at a to 90° at h', when there is no Y motion ; and the
y motion of the whole wheel merely carries the plane forward over a
greater surface of air, by the resistance to displacement of which the
weight of the wheel has to be floated.

(5) If the y velocity be equal to the forward velocity the wheel
would have if running upon a rail, the line of the curve will be parallel
to the inclination of the planes, at the several points lettered on the
cycloidal curve aa", and will be the line of the resultant direction due to
the mutual deflexion of the motions Y aud X at these points, in the
same way as r (Fig. 2) is the resultant direction when Y and X are
represented proportionately by y and x ; consequently, if the wheel be
really running upon a rail, it will remain upon the rail till the X pressure
developed by increasing velocity of rotation becomes greater than the
weight.

(6) Suppose the wheel free in air, and revolving on its axis at a rate
that, if running upon a rail, would carry it from h" to a", in making one
half-turn ; but, in the absence of a rail, we will assume that the velocity
is sufficient to carry it against the resistance only the distance h"d' (Fig. 3.)
in the time of one half-turn

The curve which the planes will actually describe in this case is
shown in Fig. 3 ; and as the planes in describing the curve have, at the

Fig. 3

a »

AERONAUTICAL SOCIETY

successive points lettered a to m in the curve, the respective angles of
inclination shown at the corresponding successive points lettered atom'
in the wheel, it is seen that the planes in Fig. 3 are driving the air before
them, wit1, an area of displacement at any point equal to the sine of the
angle which they form with the ;urve line at that point.

Moreover, in the rising curve km. the resistance which the air offers
to displacement acts in depressing the wheel, and thereby neutralizes
the upward resistance on the falling curve ah ; consequently, as regards
support to the weight of the wheel, the planes might as well assume
simply the inclination of the curve, as in Fig. 2 ; and it is clear that
this would render the lower portion of the curve of little service for the
supporting of the weight, while the curve ah or hm ao little exceeds the
half circumference of the wheel that the surface of air over which the
planes are carried, as regards the upper portion of the curve, exceeds
only in like small proportion the surface that would be come in contact
with, were the wheel revolving without Y motion, or with the axis
stationary. It is apparent, however, that the planes in the rising as
well as in the falling curve of Fig. 3, contribute to the motion Y.

(7) Supposing the wheel were suspended by long rods attached to
the two ends of the axle, these rods would naturally hang plumb when
the wheel was at rest ; but were the wheel put in motion round its axis,
in direction from 4 to c and h (Fig. 1), the inclination of the planes
would produce air resistance tending to move the wheel bodily in the
direction Y, and the suspension rods would be inclined from their
original plumb direction ; and if the length of rod were taken as the
radius l'O, and made to represent the weight of the wheel 10, the sine
of the vertical angle formed by the line of inclination of the rod would
represent the proportion which the air pressure bore to the weight 1 '0.

In this case, with a given air pressure produced by a given velocity
of the planes round the axis, the suspended wheel would come to
balanced rest as regards Y motion when the angle was reached that gave
a sine bearing the same proportion to the tabular radius that the pressure
bore to the weight of the wheel ; and as the air pressure has here lifted
the weight to a height indicated by the versine of the angle, and expends
its force in sustaining the weight at that height, it is clear that the force
would impel the weight forward in the Y direction were the suspension
rods removed, and the axle ends supported upon blocks free to slide in
the direction Y.

(8) The friction of the supporting blocks sliding upon rails well
lubricated would be for iron surfaces '07 of the weight in motion ;

or GREAT BRITAnr.

whereas, if the sliding takes place upon air, the planes in this case acting
as the sliding blocks, we have, in the first term K of Morin’s Rule for
air resistance, the co-efficient, which is of the nature of friction, as it is
independent of velocity, and likewise of weight of body, and is simply
proportional to the surface in contact with the air ; the atmospheric
pressure taking the place of the pressure of the weight of body which is
in action in ordinary friction between solids.

KA + K' V* = R in lbs.

When the area A and the velocity V are expressed in feet, the rule is

A (|W®87 + '”) = * '**■

So that, for an area of 1 square foot, the resistance due to air friction is
0 007371bs., without reference to the velocity, or to the pressure which
represents weight, due to the velocity. This, however, concerns merely
the sliding friction, due most likely to the rolling motion imparted to the
air in close contact with the surface.

(9) When the wheel moves with Y velocity, the rotating planes
describe curves, which open out wider and wider from the rim of the
wheel, as the Y motion, starting from a state of rest, increases until the
Y motion becomes equal to the motion of rotation round the axis.

In Fig. 3 we assume that the rotation of the wheel would carry it
from h“ to a" in the time of one half-turn, if running upon a rail, but
that the resistance to Y motion is so great that the pressure of the planes
can impel the air-borne wheel only the distance h"d”.

If the centre of the wheel were retained at B (Fig. 3), the force in
the rotating vanes would be expended in putting the air in motion in the
direction F1 ; but, suppose the wheel free to move in the distance ti'd'
in the time taken by the plane a to descend to ft! ) then, let F ~f + /'
represent the whole force ; M — y + y' the motion of rotation ; / the
resistance of the air to displacement under the pressure of the rotating
planes ; /' the force lost in the motion y' given to the portion of air
displaced ; we have

MF-fy=f'y'.

It is clear therefore that when, as in Fig. 2, the velocity y is equal to
the velocity of rotation, the backward loss f has come to an end, while
the force / has reached its maximum, that is, the force F of the planes
is now expended wholly on the Y path.

(10) If the wheel in Fig. 2 had only the motion of rotation round
its axis, the resistance of the plane a in its descent to ft! would at any
point be upon an area of displacement equal to the sine of the angle

AERONAUTICAL SOOtET?

formed at that point by the plane with the circular path it moved in ;
and the mean area represented by the mean sine, multiplied by the
number of planes, would give the total area of displacement which the
force F of the wheel would have to impel against the air resistance ; and
this total area is represented by A in the rule. A (K + KXV*).

(11) The definite values given in par. 8 to the coefficients K and K'
are, however, for isolated planes on a straight course. In the case of a
wheel with planes arranged radially from the axis, as in a common fan-
wheel, the coefficients determined by Morin are

A (0-00892 + 0-001907 7s) = R in lbs.,
but, as the planes in the wheels now in question are not arranged
radially from the axis, the coefficients precisely applicable would have to
be specially determined for the particular form. As, however, the
motion Y spreads the planes as shown in the curve of Fig. 2, we have to
treat the forces with reference to this curve.

The motion of displacement is assumed to be in the planes and not in
the air ; the mean angle of inclination of the curve is about 574°, formed
with the direction of the displacing pressure X ; and as at this angle
Thibault found that the ratio of resistance to projected area of displace¬
ment, is the same as when the plane surface is perpendicular to the
direction of the pressure, we employ the coefficients of par. 8.

In Thibault’s experiments the resistances determined the higher
coefficient values given in this paragraph ; but he rotated the planes round
a fixed axis, whereas here the planes are spread out upon the curve haa" ;
and in the absence of data for the precise value on the curve, we employ
the lower coefficients for isolated planes on a straight path, because the
conditions seem not to justify the employment of the higher values.

(12) In the rising curve ha, as in aa", the plane moves in the
resultant line of the two motions Y and X, but in the contrary direction
in ha to that given to it in aa".

The velocity Y being here equal to the velocity of rotation, there is
no backward force/', so that the- rising plane can contribute nothing to
the Y motion ; but in its rapid flight over the extended surface of air at
rest, ha, it contributes to the support of the weight of the wheel ; the
inertia of the bed of afr passed over in the whole curve haa" forming the
resistance by which alone the weight can be supported ; and, by reason
of this inertia of the bed of air between a and a", are the planes enabled
to draw the wheel forward with the velocity Y, as each successive plane
describes its path on a curve in advance of the curves of the preceding
planes, as shown in the dotted curves of Fig. 2.

OF GREAT BRITAIN.

(13) Th# plane which for the moment happens to be at the foot of
the curve a", might be thought to act in the same way as the friction of
a wheel upon a rail, the horizontal direction of the inclination of the
planes on the upper part of the curve enabling the vertical plane at a"
to serve possibly as a fulcrum ; but there is no motion in the plane there
at a!' to develop air resistance, and the pressure of the planes upon the
curved air path aa" takes the place of the frictional hold of a wheel
rolling along the ground.

Chapter II.

(1 4) In Fig. 4 let h "a" represent the motion Y, and ah' the motion X,

Fig. A

in the time of one half-turn of the wheel ; aa" will then represent the
resultant motion, and the angle aa' h" will be about 32° 29', the sine aA
of which is 0 53705, and the cosine h"a" 0'84354. The cosine here is the
sine of the complementary angle h"aa" ; and with reference to the sines,
as we shall presently show, the angle h"aa" relates to X pressure, and
the angle aa"h" to Y pressure. The respective sines of these angles are
components of the whole force equal 1 ’0 of the plane, and represent the
relative proportions in which this force is expended upon the two
resistances X and Y ; and

— ~ 0^53705 _ 0.6366 for y t() | for X = the tangent op (see pur. 33).
X = 084354

This simply represents the proportion which ah" bears to h"a" ; and
as the whole force is 1 -0, and the component forces together cannot be

more than that, we have

ah" = 0-53705* = 0-2884

h"a" ^ 0-84354* = 0-7110

1 0000

AERONAUTICAL 80CIETY

The spaces between the successive points a, b, c, d, e, f, a", in the
curve, though unequal, are travelled in equal times.

It is apparent from the difference in these curve spaces that, at a,
the velocity in the direction Y is at its maximuih, and that, at a" it has
sunk to zero ; and it is seen that this difference in the curve spaces is
owing to the variable rate of the motion of the planes in the path of
rotation round the axis.

(15) When ah" is 8ft., and the wheel with its twelve planes makes
one revolution per second, we have, approximately,

SI'

sec.

ft.

= 0.53 4-

= 1-47 4- „ =

= 2-00 4- „ =

= 1-47 4- „ =

= 0d>3 4- „ =

800

vel.

6 36 feet rate per second.
17-64 „

2400 „

24 00 „

17-64 „

6-36 ,,

95-90

W ere the resistance to motion to vary simply with the velocity of
motion, we would have 95 "90 4- 6 times for aa" = 15'983ft. mean
velocity for ah!' in the descent on the resultant aa" ; and as the wheel
makes one revolution in one second, the velocity of the planes on the path
of rotation round the axis is at the rate of 25 13ft. per second, and

15 983

- = 0-636 ;

2513

but as the resistance varies with V9 we square the rates of velocity given
above, find the sum to be 1855 ’238, and

t/1855-238 v , .A .

■ - - = 17 \>8ft. mean X velocity force.

6 times

At I5'983ft. uniform mean velocity the plane will descend from
a to a", and the resistance impelling it in the Y direction will be as the
sine ah' = 0 '53705, while the vertical resistance opposing the motion X
will be as the cosine h"a" — 0-S4354 ; apa" in relation to sine and cosine
representing the actual area = 1 -0 upon which these relative resistances
are developed (par. 34).

It is clear, however, that to find space for the 15 -983ft. in the given
half-second of time for apa", which measures only about 14"9ft., the plane
has to move outward on the longer path of the curve ada", and we find,
approximately, that

14 9 : 15-983 : ; apa" ; ada".

OF GREAT BRITAIN.

(13) The motion X, or the tendency earthward, is acting as freely
in the cycloidal curved path aa", or in ah" the path of rotation round
the axis, as in a direct fall from a to h", when the conditions of resistance
give the same time to each in descending from a to the level of h"a", so
that we are here free to reason as if the descent were in vertical
direction from a to h".

Assuming that the plane descends in this vertical direction, the
work in foot-pound units performed in the displacement of the air
in the path of the plane, would, per second, be at the rate of
R — A ( K + K'V*) — compressive force, multiplied by the space
in feet that the mean velocity would carry the plane in 1 second ; while
a column of still air, in transverse area equal to the area of displacement
of the plane, and of height sufficient to contain weight to balance R,
would represent the constant compressive force acting uniformly at all
points of the time, and of the space travelled at the uniform mean
velocity ; so that the weight of the column of still air merely represents,
in simpler form, the weight of force in the volume of air which is
undergoing compression under the front face of the advancing plane.

(17) Now, at the beginning, near zero at the point a, this column,
which by its simple weight merely represents the force R, would be very
low in height ; and any increase of acceleration in the velocity as the
plane fell further would only increase the height of the representative
column, to maintain the balance of column weight against the increased
weight of V'1 pressure in the plane ; and the force of inertia of the
weight of pressure in the plane represented by the weight of air in the

W v

column, at any point of the development, will be — x - , when W is

the weight of the pressure at that point ; g 32J for free standard gravity ;
v the velocity ; and t the time for which the velocity is rated
(pars. 21, 35).

The column by its weight represents the force of air resistance
offered to the plane, that is, represents the pressure of the plane, and,
as the plane with this pressure is in motion with velocity v rated for the
time t, and further, as the pressure on the plane is equivalent to weight,
and as the force of inertia here is the resistance which the weight
opposes to increase of acceleration, we have the force of inertia in the
balancing column equivalent to the force of inertia in the motive
pressure of the plane.

As the plane is exerting its pressure in the actual displacement by
compressive force of a weight of air, the force of inertia of which is

AERONAUTICAL SOCIETY

constant as regards the uniform power required to overcome its inertness
when the rate of acceleration of the velocity is uniform, but is accumula¬
tive in respect to the weight’s retention of the power expended on it ;
thus, we have, employing the velocity v for 1 second for free gravity,

vt 32J* x lib.

with a weight of 11b., — — = — - — — - = 16 A units of work

6 2 g 2 x 32*

accumulated or stored up in the lib. weight in motion, ready to be
thrown out into sensible form upon any obstruction arresting the motion,
but in its passive stored-up state remaining perfectly independent of the
foot-pound work which the lib. weight would perform in moving through
air, supposing the resistance of the air to render the velocity uniform
from the point where the given 32ift. per second rate was reached.

The quantity of accumulated work thus stored up within the weight
is determined by the rate of the velocity v at the point of observation,
and is ever the same quantity for a given rate of v, irrespective of the
time allowed for the accumulation, or for the development of v ; it is
clear, therefore, that when the plane with acquired X motion is shifted
edgewise by the Y motion on to fresh air at rest, and thereby shifted
from the body of air to which it has already imparted the given
X velocity (which is v of the above equations), it requires, from the store
of accumulated inertia work belonging to its own pressure weight, to
expend force in overcoming the inertia of the fresh body of air ; and as
the accumulated force of inertia in the pressure weight of the plane was
simply equal to the accumulated force in the body of air shifted from,
the force of attraction between the earth and plane supplying the
constant motive power in the plane to continue the work, it is evident
that the new body of air shifted on to will require all the force stored in
the plane to give it motion equal to the motion in the preceding body,
and this will be equivalent to a fresh start for the plane, and there will
consequently be as many fresh starts as there are distinct shifts on to
fresh air in the Y space travelled.

The force of inertia developed by accumulation in the time required
to make one shift may then be termed the unit of force, which, multiplied
by the number of shifts in the time of the given Y velocity, gives the air
inertia resistance R' for one second ; so that as the weight of the
R columns of still air, which represent the compressive force due to v* of
the plane, is of equal value to the weight of pressure in the plane,
power in the plane is required to balance as many R columns as there
are distinct shifts on to fresh air in the Y space travelled.

(18) The mean velocity is 15 '983ft., but as the plane in travelling

0* GREAT BRITAIN.

the curve experiences resistance due to the square of the successive
velocities that give this simple mean, we employ the square mean given
in par. 15.

When the area of displacement is perpendicular to the direction of
the motion, the X resistance to the plane at the mean-square uniform
velocity of 17'58ft. per second, is

sq. ft. / K Kl \

1 0 (000-37 + 0 0016 X 17-68’)= " 5021b. w p«MUr..

(19) But, as the mean area of X displacement is only 0'8485 of the
value 10 for the full area displacement were the plane constantly
perpendicular to the direction of the path it moved in, we have the mean
air resistance only 0’502 x 0 8435 = 0 42341b., which we employ as the
mean constant force for each square foot of plane at the velocity
named; and as we have thus reduced the force of the air pressure
or resistance to the mean constant value for the whole curve which
represents one turn of the wheel round its axis, we are free to employ
0'4234lb. as the weight of the mean column of air which would
balanee the mean pressure ; and as the mean breadth of the plane in the
direction Y is assumed to be 0 '8435ft., we have this unit area making

215*1 3ft

— = 29 '792 shifts of 0'8435ft. each, on the Y space of the whole

0-8435

curve haa", so that there are 29'792 distinct columns of air of the mean
0 '8435 value requiring the force of inertia due to the given velocity to
be developed in them, by the pressure of the given X velocity, in place
of one column only, were the plane, starting from a, to move on a
straight path perpendicular to its area of displacement. The X velocity
is 17 '58ft. for one second of time, and one second is allowed for the plane
to act upon the inertia of the whole mass of air, which has its area of
resistance on the curve hap.", and which we say is equal to 29792 mean
columns of inertia resistance ; so that we have the 0 '8 43 5ft. inertia
resistance {par. 20) multiplied 29792 times on the curve, and the
multiple quantity is equal to the weight which the plane area, moving at
the given rate upon the curve, will sustain in air (pars. 20, 22).

(20) As the time assumed for one turn of the wheel, and therefore
for one complete curve, is one second, and as there are in effect 29792
successive columns of air to resist the pressure of the plane by the inertia
of their weight, we divide one second by 29792, and likewise 15'983ft.

velocity, to get

the - for
t

the time of one clear shift of position of the

plane on the curve haa".

AERONAUTICAL SOCIETY

We employ the mean of the simple velocity here, in place of the
mean F*, because the result We now seek is ruled by the rate of
acceleration, and in the mean simple velocity 15 983 we have the mean
rate, then

100 sec.

and

29-792
15-983ft.

= 0 0335 for t.

= 0 532 for v.

29-792

then, employing the 0 8435 mean value of the resistance, which is

0 42341b., we have — x -
9 t

0-42341b.

0-532

0-211b., constant

32 18 0 0355

value of the inertia of 0 42341b. weight of air, at the given mean
rate of acceleration from zero to 15 983ft. velocity in one second, and
0"21 x 29-792 shifts = 6'25631bs. resistance of the air inertia in one
second, on the whole curve haa", for each square foot of plane.

(21) At the rate of acceleration due to natural gravity, with
g — 324ft. per second, the constant value of the pressure weight would
be simply the weight O' 42341b., because 321 for g represents in the form
of motion the natural force of the earth’s attraction, close to earth ; and
this force in constant action upon matter gives simply the effect called
weight, and in this case the equation would be

W v

- X — —

9 1

0-4234 32-18

= 0-4234.

32-18 1-0

(22) As the active force of the plane pressure is developed on the
falling curve aa", and as 0 4234 is the mean X pressure per square foot of
plane area, and, further, as the X pressure area is in direct relation to h"a",
which measures 12"566ft., we determine the resistance by the pressure on
the curved path aa", and find it closely approximating to the inertia
value for the whole path haa" ; it being borne in mind here that the
inertia of air, as of anything possessing weight and come upon in a state
of rest, concerns displacing force simply, irrespective of the direction that
the force is moving in.

The rising planes on the curve ha, though in motion contrary to the
direction of the X pressure, are sustained in common with the planes on
aa", by the inertia of the elastic air bed that they travel on in rising, the
assumption being that the force on the falling curve aa" is taking effect
in displacement of the wheel and not of the air.

29-792

0'4234 x — - — = 6-301bs. resistance for the path aa" ; but as the
pressure which meets with this resistance is imparted by a plane surface,

0* GREAT BRITAIN.

inclined so that the air, to get relief from the imposed pressure,. must
either suffer itself to be displaced to the rear edge, or else support the
pressure so as to let the plane slide ; in the latter case, which we assume
to be what happens under the conditions previously named, we have the
plane displaced and not the air (par. 36). And as the inertia of the air
is the only sustaining force, we have the displacement motion Y of the
falling planes in aa", keeping the rising planes pressed against the air
they slide- upon in ha, so that the inertia of the whole elastic bed of air
is made to bear the X pressure of the gravity of the dead weight, and the
faces of the rearward or rising planes are prevented from opposing the Y
motion by rising with their angle of inclination coincident at all points
with the angle of the curve they travel on.

(23) We will now assume that the weight to be supported by the
plane is 6'31bs. , and, employing Morin’s Rule in inverted manner,
will find the velocity that wijl give air resistance to balance this weight,
s o as to float it on a balanced horizontal line : thus —

6 -—~ ^Q73/ = 3933 = F*, and ^3933 = 6271 = F; then

•3933 _ 3933
2 g ~ 64-38
61-09

= 61 ‘09ft. space fallen to give 6271ft. velocity; and

14-896
plane to move

= 4‘lOllft. mean fall in the time taken for 1 square foot area of
1 th

part of the distance h"a" ; then

14-896

4-1011 x 64-38 = 26402 = F2, for 47011ft. fall; and

y/ 264 02 = 16 24ft. = F, for 41011ft. fall,

K' x F* = 0 0016 x 264"02 = 0"4231b. constant X resistance per
square foot of plane perpendicular to X, for the F2 due to the time of
one clear shift in the direction Y ; and O' 423 x 14 "896 shifts = 6'31bs.
resistance for X in the whole Y distance h"a".

(24) Now in this we have the square foot area of plane perpen¬
dicular to X at the 16 24ft. rate of velocity, whereas the plane changes
its angle of inclination from 90° at a to 0° at a", in falling along the
curve aa", thereby giving a mean area of 0 8436 square feet only ; and
as the value of velocity force is as F2, we have —

F* F* Area. Area.

17*58* : 16*24* :: 1*0 : 0-8435 nearly.

309-056 : 264 02 : : 1*0 : 0 8435 „

The ratio would be found strictly as 1 to '8435, were the mean-force
velocity 17'58 on the falling curve determined with greater precision
than by the mean Bimply of six spaces, a» in par. 15.

ASTRONAtJTlCAli SOCIETY

(25) A heavy body starting from a state of rest in space near earth
will have only the natural force of gravity, with the velocity accelerating
at the natural rate of 32ift. pSr second ; and the 62*7 1ft. velocity due to

6271

a fall of 61*09ft. will require for its development 1*94 seconds;

o2*

and if it weighs 6*31bs., and has an area of 1 square foot, and is moving
in a straight course to earth, perpendicular to the area of resistance, the
velocity will become uniform at the velocity named.

In the wheel the plane with X motion starts from zero, corresponding
to a state of rest, at a ; but the Y motion brings it into contact with the
displacement area of a body of air 14*896 times the displacement mean area
for a straight course earthward, and we have the force of 62*71* X 1*0
equal to the force of 16*242 X 14*896 ; the greater volume of air with its
low development of inertia force here taking the place of the less volume
with its higher development (par. 17) ; and we have already seen that,
owing to the change in the angle of inclination of the plane, the mean
force of nearly 17*582 X 0*8435 is equivalent to 16*24* X 1*0.

(26) The centre of gravity of the weight is in the axis of the wheel,
and as the motion by which the planes develop sustaining resistance
equal to the weight is on a circular path round that centre, we have the
Y component of the plane pressure propelling the sustained centre in the
Y direction (par. 44).

(27) We have yet, however, to determine the value of the planes
on the curve in relation to horizontal or Y motion.

The 0*8435 value of the force exerted by the planes has reference
merely to the resistance opposed to gravity, the pressure producing the
resistance being exerted in the purely vertical direction X, and the
resistance simply balances the gravity of the load.

(28) When the wheel (as in Fig. 1) has only the velocity of rotation
round its axis, the pressure of the plane A in starting downward begins
at zero, and becomes equal to 1 only on reaching the bottom position
at h ; the rim of the wheel in this case carrying the points A and h along

he path of rotation with equal velocity.

(29' In Fig. 2 the extension of the path on the curve enlarges the
air surface op which the plane a has to act in a given space of time, and
thereby in effect enlarges the supporting area, or the area of resistance
to the force of gravity, the extension of the path upon the curve giving
the greater inertia of a greater weight of air to oppose the force acting
in the plane.

The enlargement of area, however, has taken place by the

Of GREAT BRITAIN.

horizontal extension of the path, while the vertical space ah." remains
constant, and with it likewise remaining constant, the mean simple
velocity 15 '983ft. for X ; so that, as the successive times marked a, b, e,
d, e, f, a ", on the curve, are equal, and coincident with the times of
rotation a, b', c', d', e, f, U , on the rim of the wheel ; and further, as the
angles of inclination of the plane at the successive points on the curve
thus lettered are precisely the angles at the coincident points on the
wheel rim, we have the area of pressure upon which the resistance X is
developed on the curve in Fig. 2 equivalent to the area upon whiqh the
pressure X is developed in Fig. 1 ; because the extension of the path
consists simply of the flattening out, in the direction Y, of the wheel-rim
ad 'b! which carries the planes, the planes assuming the successive angles
without reference to this ; so that the plane A of Fig. 1, represented by
a of Fig. 2, is carried forward in the Y direction the distance h"a", in
addition to the X space ah!' which it would descend if merely rotating
round the axis of the wheel, as in Fig. 1.

(30) Then, as regards air resistance due to motion, zero being at
the point A in Fig. 1, and at the point a" in Fig. 2, the plane in Fig. 1
has its maximum force pressing in a way to produce Y motion, and in
Fig. 2 has it developing X resistance ; hence, when the pressure Y on
the arc Aeh of Fig. 1 is represented by 10, the angle which gives the
0 6366 ratio tangent force for X (pars. 3, 14) opens from h with A as
centre ; that is, the direction of the X component force is parallel to Ah.

(31) Whereas, when the maximum developed resistance X, on the
curve ada" of Fig. 2, is represented by l-0, the mean ratio angle may be
taken as opening from h ", with the zero point a" as centre ; and we then
have the 0‘6366 tangent ratio for Y, that is, the direction of the Y
component force in Fig. 2 is parallel to h"a". We are free to take the
angle in Fig. 2 as opening from h" with a as centre, and, in that case,
the Y ratio will be represented by the cotangent of the angle which has
a" for centre.

Chapter IV.

(32) In explanation of the mean ratio we may here observe that,
referring to Fig. 4 and employing a"a as the radius 1 '0 representing the
whole force, equal 1 '0, the length of the complementary arc ya, belonging
to the complementary angle aa"y = 57'2957°, is equal to the length of
the radius ; and dividing this number of degrees in ya by the 90° of yg,
we have

67-296°

0’6366 ratio.

AEfcONAtmCAli SOCIETY

Further, the complementary arc ay is in the same ratio to the arc ag
that the cosine az is in to the sine aJi' of the angle aa"h" ; and as h"a"
is equal to az, we employ the tabular values and get the ratio
ah"

= wj, as in par. 14.

Moreover, we have the whole-force radius a"a represented by a"y in the
same ratio to the cotangent yx, as ah" is in to /t"a" ; thus —

a y

= wg

1-000

1-57

0-6366.

And yet again —

Rad. X tang. = a"g X wg = 10 X 0‘6366 = 0.6366.
Consequently we have the cosine h"a" relatively representing the radius
for the whole force 1*0, and the sine ah" the relatively proportionate part
of this whole force which, in the turning of the angle of inclination of
the plane from 90° at a to 0° at a" is developing Y pressure.

(33) JThe sines, tangents, &c., employed in Fig. 4, pimply exhibit
in graphic form the relative proportions of the respective forces or motions,
and are in nowise dependent for their value upon their individual lengths
or the individual spaces enclosed by them, the value being ruled solely
by the angle ; thus, in par. 14, having made ah" the radius, we have for
the angle aa"h" (equal to the angle 2a a") the tangent value represented
equally truly by op ; and we would have the tangent represented equally
by a still shorter line were we to take as the tabular radius the actual
radius at of the wheel.

(34) In the paragraphs preceding this, we make the resultant line
of force aa" represent the tabular radius for the whole force in order to
exhibit in direct form in relation to it in a"g, the proportion represented
by wg, which is developing resistance to give Y motion.

Now, as the whole force in the radius aa" (Fig. 4) is 1'0, and as h"a"
is the component developing X resistance, we have h'a = 0’6366 of h"a",
developing Y pressure ; and as {pars. 19, 32) the whole force l'O is
represented by the constant pressure R — 0.42341b. air pressure per
square foot of plane, we have for Y force

0‘4234 X 0'6366 = 0-26951b. pressure Y.

The ah" ratio 0'6366 is in relation to l'O for h"a" ; but as h"a" is only
0‘8435 of the actual area of the plane represented by a"a, it is clear
that the 0'6366 has reference to the 0'423ilb. resistance, which is
0-5021b. X 0-8435, as in par. 19 ; otherwise we would have

sine.

0 5021b. X 0-53705 = 0'29651b. pressure Y.

Of GREAT BRITAIN,

(35) The Y velocity is assumed to be at the rate of 25'13ft. per
second, but it is evident that the plane, at any point, can exert pressure
to give Y motion only in the ratio of its area of Y displacement
perpendicular to X at that point, with the force there due to the
velocity X.

Treating the Y pressure as we treated the X pressure in par. 20, to
get the force of inertia of the body of air passed over, we have
W,v 0 2695 0-532

g X t 32-18 X 0-0335

= 0 '138091b. constant value of the

inertia of 0"26951b. weight of air column resisting the given rate of
acceleration; and as there are only 14896 mean area shifts of the
inclined plane on to new air at rest in the forward or falling curve ada",
we have 0*13809 X 14 896 = 2 05691bs. Y resistance of the inertia of
the air upon the whole falling curve per foot of plane passing over it.

(36) As air, however, is an elastic fluid, and the formula here
employed is for weight simply, without reference to elasticity, and as a
certain measure of compression of the air in contact with the plane, and
consequent yielding, must take place before the force of the compression
equivalent to the given weight can be communicated to the air beneath,
the force of inertia here determined forms merely a standard by which
to determine the value Qf the pressure in the plane in motion ; and, to
keep the question in simple form, we do not in direct manner compute
the extent to which the air may yield under the pressure, because the
motion of the planes upon the curve is variable ; and as this motion is the
motion of displacement, we have it in the planes and not in the air, as
soon as the point is reached where the extended air resistance balances
the dead weight borne by the planes {par. 22).

(37) The actual pressure developing Y velocity is 0 "26951b, per
square foot of plane, and as the velocity of rotation round the axis of the
wheel that gives this pressure is assumed to carry the wheel forward in
the Y direction at the rate of say 25ft. per second ; and as the air
resistance per square foot of perpendicular surface at this rate is

r007371bs., we have *

02695

3 738 as the ratio of the required pro¬

pelling area with its 17 "58ft. mean F4 power {par. 151 to 10 for the vertical
area which will offer direct resistance to the forward motion Y only ;
that is, when the vertical front face area of the body is equal to part
of the mean propelling area, the power and the resistance will be
balanced so as to make the Y motion uniform.

(38) The plane advancing constantly edgewise on the curve, has

AERONAUTICAL SOCIETY

the distance haa" (Fig. 2) equal about 32ft., to travel in one turn of the
wheel, here assumed to occupy one second of time ; but as the air
resistance varies with the square of the velocity, we square the successive
varying rates of the velocities in the 12 spaces into which the curve is
divided, and divide the sum by 12, and the square root of the quQ.tient is,
approximately, the mean velocity to which the actual resistance on the
plane edge is due ; thus, the sum of V 2 quantities is about 15092 ‘8, and
this divided by 12, is 1257 73, then

y/ 125 7 ’73 — 35 • 46ft. = V for mean edge resistance R on whole curve.

As, in the rise from h (Fig. 2), the edge resistance tends to depres
the wheel in the direction X, while, in the fall toward a", this
X depression is balanced by the contrary tendency, we have the
Y resistance R on the edge, in the same ratio to the whole edge
resistance on the curve, as found for the face X resistance R, in par. 15,
viz., 0’8435 to l'O ; so that the area of effective resistance for 1 square
foot of edge is 0 8435 ; and
ft. area.

0‘8435 (0'00737 + 0-0016 x 35'462) = l-70361b. R for mean constant
resistance to Y on the curve, per square foot of edge area.

(39) But the motive power will have to overcome the edge
resistance at the full rate of 2 0191bs. per square foot of edge area
perpendicular to the curve path ; so that as we now assume that there
are 180 lineal feet of edge in the planes, which have the velocity named,
it is clear that the planes must be thin, or have their thickness tapered
from the middle. We do not include this edge resistance in the
0 42341b. resistance per square foot of plane area, and to give it a
precise value per square foot of face area, would require the precise form
and fashion of the plane to be here considered, and that lies outside of
our present purpose ; suppose, however, that the edge area for planes
and stiffening-rods were equal in effect to only Ath, or 0’0417 square
feet, perpendicular to motion, per foot of plane ; then 0 0417 X 20191bs.
= 0 084191b. per foot of plane, and 0 08419 + 0 4234 = 0'50751b. for
motive power (par. 58).

Chapter V.

(40) We will now suppose the wheel resting on the ground, and
started in motion from a state of rest, to acquire X pressure on the
planes and Y velocity to float it. The weight to be floated by each
square foot of plane is 6‘301bs. (par . 22), and the resistance R developed

Or GREAT BRIT Alt,

for Y by the pressure of the plane, in the falling curve ada" is 0’26951b.
per square foot of plane (par. 84).

(41) The diameter of the wheel is greater than usually employed
for wheels that run upon rough ground, and it will surmount the rough¬
ness with proportionately greater ease ; but, with a given lightness of
frame, greatness of diameter implies weakness.

0*30

(42) The Y power is - -- - = 23 38 part of the weight to be

U’Joyo

oarried ; and as the Y power here acts in the manner of traction power,
and as the ratio of 1 for traction power to 30 for load borne upon the
axles of ordinary wheels, is common where the surface of the ground is
otherwise than hard and smooth ; and further, as the resistance to mere
rolling on a surface not hard and smooth increases with the velocity, and
the velocity proposed for the wheel before it leaves the ground is high ;
we will assume that, while on the ground, the Y traction developed in
the falling curve is exerted only in overcoming the rolling and the axle
resistance ; and as all that the purely X pressure of the planes disposed
as shown in the curve of Fig. 2 can do is to float the dead weight, so
that when the X pressure and the weight are balanced, the Y pressure
may propel it horizontally, it is clear that upon a level, with the planes
inclined as in Figs. 1 and 2, the wheel, with the X pressure and the
weight thus balanced merely, could not rise above the ground ; though
the pressure of the weight, transferred to the planes, would relieve the
pressure on the ground, assuming the wheel strong enough to move on
ordinary ground with sufficient velocity ; and on reaching a sudden
declivity in the surface of the ground, it would float out upon the air.

(43) If, however, the dead weight were only 6'01bs., and the
X pressure of the planes were 6 '3011)8., this would be equivalent to an
upward pressure force of 0'301b. per foot of plane, and the wheel would
rise with the force of that upward pressure, on a rising resultant.
Moreover, if the planes were inclined as in Fig. 5, say by the canting of
the platform inside, the rise would be more ready.

(44) Were there no velocity of rotation round the axis, but if, in
place of it, the planes were spread out as shown in the curve of Fig. 2,
and allowed to fall to earth to acquire the velocity that w'ould give
resistance equal to the gravity of the weight, in the fall to give this

# v

velocity, the rate of acceleration - would gradually lessen, until the

velocity became uniform at the point where the air pressure and the
weight became balanced ; but, to maintain this balancing pressure, the

AEBOtfAUTICAIj 80CHTY

series of planes would have to continue falling at this uniform velocity ;
whereas, when the planes are rotated round the axis of the wheel, we
may regard the weight as centred in the axis, and the velocity that can
be got only by falling, when there is no rotation, is here got by the
velocity of rotation, with the axis and the weight centred thereat,
relatively at rest, for the planes are revolving round it (par. 26).

(45) When the ground slopes at the angle of about 2° 14', which
gives a rate of inclination of about 1 for rise to 25 "566 for slope, equal
to 1 of fall for each turn of the wheel, we have this 1ft. of fall in addition
to the mean velocity, 15‘983ft. Roughly, this would make the mean-
force velocity about 1 + 17 '58 = 18'58, and this greater velocity
substituted for the 17'58 in par. 18, will give a greater resistance for X
in the curve, calculated to sustain a greater weight than 6'301bs., or,
equivalently, to carry 6'301bs. weight horizontally forward clear of the
ground.

(46) If, however, in order to raise 6'301bs. from the level ground
with the velocity due to one turn of the wheel in one second of time, the
centre to which the angles of inclination of the planes converge be upon
*he rim in the rear of a in Fig. 5, so as to keep the planes always at the

Fig. 5.

angle of say 2° 14 with the path of motion in the curve, we have the
planes exerting a rising tendency somewhat similar to the tendency last
referred to, to move away horizontally from ground that slopes at this
angle. A certain measure of power, however, is lost to Y in the case of
Fig. 5.

(47) W ere the wheel going against the wind it would require less
than a velocity of 25ft. per second in the wind to neutralize the
Y impelling force of the plane on the falling curve, because the plane in
the lower time spaces d, e, f, a", is coming to a halt as regards Y motion,
and, during the ith of a second, while travelling the spaces fu", hi (Fig. 2),

or great BRiTArx.

is nearly at right angles to the direction of the motion of a contrary
wind. For another ith second in travelling the spaces ef, ij, the pro¬
portion of the whole Y space ha" for 1 second which it travels, is at the
rate of about 7'68ft. per second ; and for another 4th second for the
spaces de,jk, only at the rate of 18 '60ft., the rate for the spaces cd, Id,
being 31 '56ft. ; it is clear, therefore, that if an attempt were made with
this particular form of wheel to rise from the ground, in the face of a
breeze at the rate of 25ft. per second, or 17‘4 miles per hour, it would be
hopeless ; indeed, there are few land-birds that can fly against a breeze
of this strength ; and those that may can make but slow Y progress even
with the expenditure of more than usual power. A breeze acting upon
their thin wings may help them to rise, but once off the ground they
may be seen in ordinary circumstances to fly away on a line that forms
a wide angle with the direction of the wind.

(48) A plane, launched from a to descend on the straight
resultant apa" of Fig. 4, with power to give it a Y velocity of 25ft. per
second, measured in line with h"a", would — neglecting edge resistance —
have its propelling power balanced, or neutralized, by a horizontal
current of wind of equal velocity to this acting directly against it, in line
with a"h”, and the Y displacement area would be consequently powerless
to produce motion in the Y direction, because the air in contact with the
lower face would not wait to bear the pressure ; and the wind in arresting
the Y motion would have the same force on the projected Y area of the
upper face that the corresponding area of the lower face would have
were the wind to give up its motion to the plane ; and as the air beneath
is receding from the pressure, the weight of the plane is unsupported,
the plane falls, and is at the same time blown backward.

Greater velocity on the path apa" would bring the plane down
X-ward upon the receding air at a quicker rate, so as to derive support,
but this would require force greatly in excess of the power available in a
wheel such as we have under consideration.

AERONAUTICAL SOCIETY

Chapter VI.

(49) We have now to consider the means by which the planes may
be made to take the angles of inclination Bhown in Fig. 2, and employ
Figs. 6 and 7 to exhibit them.

Fig. e.

As the angle changes 90° in passing from a to h\ or from d' to Id of
Fig. 6, and as the' plane at a is horizontal, and at h! is vertical, we
connect, by means of a rod, one edge b of the plane a with the end c of
a lever projected perpendicularly from the lower plane h', and have an
eye m the middle of the rod working on a pin e, which forms one of the
series of pins shown in Fig. 7. Each rod may have, about midway
between the middle pin e and Pig. 7.

each of the* outer ends, a few
spiral turns as shown in
Figs. <5 and 8, to give elasti-

- 1

-1

city in the event of the light
wheel rim changing form ^

when running upon the ""“I
ground.

Now, the plane h! on

)

rising to a, has made only
^-revolution on its own axis ;

. L

OF GREAT BRITAIN.

and it makes one whole revolution only for every two made by the
wheel ; and, as the rod is centred on the pin e on a circle concentric with
the wheel, and as the pin e for every revolution of the plane round its
own axis takes twice the time to describe the circle e, e', e", e"', e, that
the wheel takes in describing the circle a, d', h', U, a, we have to restrain
the motion of the pin e round the wheel axis to half the motion of the
wheel, and do so by means of gearing connected with the motive power ;
but, as shown in Fig. 8, we can do so only by cutting the wheel-shaft
say at the points c and d, to get this half-motion given, say at d, to the
bar c, which passes through the hollow short shaft c to the series of crank
pin-plates shown in edge view in Fig. 7.

These plates are shown connected together by means of the pins
alone, one pin to each interval ; no further support can be got, because
the rod which is centred on each pin traverses the whole face from e to ee"
(Fig. 6) in each revolution of the plane round its axis, as may readily
be seen were thp wheel at rest, and the two planes a and K connected
by the rod be rotated round their axes ; and similarly, as the rod
traverses the whole area between the circle described by the edges of the
plane in rotating once round its axis, the ends b and c work on the pins
of V cranks formed in the plane spindles, close to and outside of one of
the two wheels, as shown in Fig. 8 ; as the planes are balanced on their
axes, however, the axis being coincident with the centre of pressure, the
connecting-rod be has little stress to bear.

The cutting of the wheel-shaft is an objection, as it throws the work
of keeping the frame in form upon the stiffening-rods between the wheel-
rims, parallel with the planes ; but if connecting-rods b c are employed,
there is no alternative.

(50) Cords, and cord pulleys upon wheel shaft and plane spindles,
in place of connecting-rods and ernnks, would enable the shaft to be kept
whole ; but reliance could not be placed in cords to give the planes the
required angles ; besides the tension needed in the cords would
materially increase the friction of the bearing journals.

(51) In Fig. 8, upon the suspended platform j, we show the
position of the motive power engine at g. The cutting of the main shaft
would throw the greater stress upon the wheel which has the engine-
crank /, and upon the rim tie-rods which bind the two wheels together,
were the motion not transmitted directly to the second wheel-shaft c,
across the space dc, by means of the spur pinions and shaft k. We here,
however, give less heed to these internal arrangements than we might
were the assumed power of the planes to sustain and propel weight in
air established experimentally.

AERONAUTICAL SOCIETY

(52) The machine in motion, with a man inside, would have
somewhat the appearance of one of those whirling wire cylinders seen
sometimes attached to mouse-cages, whatever the man inside might
think ; however, these cylinders did in nowise originate the idea. Access
to the interior can be got by having one of the middle planes between
the wheels squarely hinged at one end, and securable by a cotter at the
other.

(53) Assuming it had the power of flight, a wheel constructed
simply as described could go on a straight course only ; and as the
rotation of the wheel-frame round its axis, and the crank-bends in the
line of shaft at b and /, prevent any connexion with steering appliances
outside of the frame in the spaces l and m, a plane, hinged vertically in
the manner of an ordinary rudder, inside the frame, and free to move to
the side on which the steering pressure is required, might be found to
give sufficient steering power.

(54) Were the rotation of the wheel stopped, with the planes
maintained at the angles shown in Fig. 1, the wheel would at once begin
to descend to earth, because the “work” stored up, or accumulated in
the weight, and due to the previous Y rate of velocity, would quickly be
consumed by the resistance of the air upon a displacement area so great
(par. 47) ; so that there could be no quiet floating such as is witnessed
in the case of large birds with outstretched wings ; the wheel, therefore,
must be constantly rotating if constructed simply as here described, and
its Y velocity on the air path can never quite equal the velocity it would
have upon a solid path or rail (par. 36).

Or GREAT BRITAIN.

(55) With the planes connected by means of the rods shown in
Fig. 6, and rotating on their own axis, it is not a simple matter, for
quiet floating, to devise handy means to make them slope uniformly in
the direction Y ; nor are the conditions much simpler for the means to
keep the same edge of the plane always the leading or front edge ; in
which case the plane would not rotate upon its own axis, but, starting
horizontally at a, would oscillate a certain number of degrees in assuming
a variable slope for Y pressure, on the falling curve aa", and be
horizontal again at a"; and the range of the arc of oscillation would be
ruled by the pressure required to overcome the resistance to the Y motion
employed.

In connection with Fig. 9 we shall presently speak of planes made
to oscillate thus, and will endeavour to show their force when thus in
action.

(56) To keep the planes of Fig. 1 off the ground, when the
diameter of the circle in which they rotate is 8ft., the outer rim of the
wheel may be 10ft., which will keep the planes 6in. clear of the ground.
In running along the ground this 10ft. circle will in one turn run a
length ha" (Fig. 2), measuring 31-416ft., whereas the 8ft. circle in one
turn would run only 2.V13ft. ; but as the spaces between the successive
points a, b, c, d, &c., in the smaller circle, occupy the same time in the
motion round the axis of the wheel as the corresponding points in the
greater circle, we have the plane at the highest point a still horizontal,
and at the lowest point h' vertical ; and, as the common centre of the
wheel is possessed of Y motion at the 31-416ft. rate, and the planes have
rotation motion at the 25 ‘13ft. rate, we have the curve flatter than when
the wheel is in flight off the ground on a free air path, and have the
velocity that gives the edge resistance (par. 38) increased by the extent
of the difference 31-416 — 25-13 = 6 28ft. ; and in the middle of both
the rising and the falling curves 1m and aa", have the planes dragging
at the expense of the motive power ; but as the drag is on the lower face
in the rise from h to a, we have here an upward drag-pressure counter¬
balancing the downward drag-pressure on the upper face in the fall from
a to a" ; and, further, as we have in the extended air bed of the longer
flattened curve the inertia of a greater bed of air, we have the balanced
drag in part compensated by the greater X support at a.

AERONAUTICAL SOCIETY

Chapter VII.

(57) We will now multiply the pressure for 1ft. length of plane by
the number of feet length assumed in par. 39 ; add the force required to
overcome the journal friction ; and the friction of the engine — assuming
steam to be the motive power ; thereby to get the total weight of constant
force required in the engine. Then, for a given pressure of steam, we
will find the area of piston that will supply motive power to overcome
this resistance ; and the number of strokes of this piston that will expend
the steam formed from 1 cubic foot of water at the given pressure, will
give the number of turns of the wheel per 1 cubic foot of water
evaporated, and the power of the engine if derived from steam actually.

(58) As the edge area of the planes is a resisting surface altogether
unproductive of useful effect, we have it acting simply as a drag upon
the motive power, and therefore a consumer of the Y pressure exerted
by the face of the plane ; and as only 0'8435 of the whole edge resistance
equal TO, is directly opposed to Y motion, we have, for the assumed
0'0417 square foot edge area per foot of plane (par. 39), 0'084191b.
x 0'8435 = 0’0711b. to be overcome Y- ward by an equivalent part of
the Y propelling power ; then, as the inertia force of 0,0711b. at 35 ’46ft.
velocity is 0,0781b., and we have 180ft. of edge, 0'078 x 180 = 141bs.
acting against Y air inertia ; further, as the inertia force of 0'26951b.
at 1 5*98ft. velocity is 0T337, and we have say 180 square feet,
0T337 x 180 = 24'061bs. resistance approximately representing the
stability of the air as an abutment to the Y pressure, the drag due to
edge resistance tending to produce a curve slightly of the nature of
Fig. 3, so that 24‘06 — 14 = lOlbs. Y impulse free to overcome the less
rate of resistance of the wheel-rims and arms, and of the bulk of the
dead weight on the platform. The motive power the while has
0*0841 91b.‘ x 180ft. of plane edge = 15T51bs. for the whole curve had' ,
to be added to 0-42341b. x 90ft. of plane face in aa" = 38 Tibs. ; so
that 38T + 15T5 = 53’251bs. constant air resistance on the planes.
In Chapter XIII we shall endeavour to show that in relation to X the
propelling impulse is in the falling curve, meanwhile we may assign
values to certain of the forces.

In the natural gravitation of the weight earthward, the whole bed
of air in the curve will act in supporting the weight, and the action of
the planes will be that of sliding over an elastic bearing surface ; and as
the 15 9 8ft. velocity is about one-half the natural standard rate for
one second, with the force of inertia developed to about one-half the

OF GREAT BRITAIN.

weight, we found it convenient to represent the sustaining power by the
whole pressure of one side, viz., the planes in the falling curve aa."

The mean time per shift of plane when the wheel makes one
revolution per second is 0'0336 second ; the velocity due to a natural
fall in this time is l'08ft. ; we assume the weight of body to be 2811bs.,
which is T561bs. inertia per square foot, and as the velocity in air to
give pressure equal to this so as to produce uniform motion is very
nearly the velocity of free gravitation in space in one second, say 32J ;
moreover, as at 32»ft. velocity for one second, the force of inertia rises
to equality with the weight of body, and would be greater than the
weight of body if the velocity rose higher than 321ft., and would
therefore in a start from zero require force additional to the force of

1*00 800.

gravitation, we have as follows : — - — — •— = 0-0336 second per shift :
6 ’ 29-78 shifts ^

in thi3 time the natural fall from zero of any weight is about 0 018ft.,
and the velocity due to this fall about T08ft., and we employ these
quantities as standards.

Then, as we assume (in the absence of experimental data to
determine more particularly) that in sliding over the extended bed of
air the planes in one second of time fall a space which is a multiple of
the mean unit fall in the unit fraction of time for one shift, we have —
0-013 x 2978 shifts = 0 536ft. fall in one second, the natural standard
velocity due to which is about 5‘87ft., which we assume to be the uniform
rate of the earthward tendency when resisted by the shifting of the planes,
sq. ft.

0 843 (0 00737 + 0-0016 x 5-872) = 0 05261b. constant pressure of
resistance per square foot of plane : 0"0526 X 180 sq. ft. — 9"481bs.
constant force assumed to be in uniform action from zero for the given
area of planes, which are here for the moment assumed to be falling
vertically, and supported by a bed of air equal to their own area only ;
then 9-48 X 2978 shifts == 282’31bs. aggregate for one second of time,
and this is equal to the inertia force resisting the planes in the
rotation of the wheel.

(59) Next, as the sustaining pressure X per square foot of area is
6-301bs., due to the inertia of the air travelled on {par. 22), we have
6'301bs. x 90ft. in aa" — 5671bs., because we have the resistance of as
many columns of air as there are shifts of plane, which makes the work
performed in one revolution of the wheel a multiple of the force of the
unit 'shift of plane at the given X velocity ; this, however, represents
the weight of pressure, whereas the inertia force is less, thus

AERONAUTICAL society

567

32-18

,X 15*98 = 2811bs. sustaining power of the air resistance, and

assumed to be the weight of the wheel and its load. This weight is
sustained only by the action of the planes over an extended bed of air.
with the constant X resistance equal to 38'llbs. as felt by the motiv
power ; consequently, in the form of friction due to the motive o'
propelling power, in the journals of the plane spindles, we have only tht
above 38 -1 + 15 15 = 53*251bs. resistance; and this will be in part
reduced by the gravity of the weight of the planes acting in opposition
to the upward pressure of the air resistance in the planes. And as
regards the part the planes have in the friction due to the whole pressure
= 5671bs. sustained, we have it in the friction between the surface of the
plane and the air-bed travelled on, which may here be neglected (par. 8).
But as the weight of the wheel-frame, and the load upon the platform
inside, is borne by the planes, and therefore produces journal friction on
the plane spindles that support it (further, as the weight of the planes
is here undetermined, and as the power needed at the engine crank to
overcome the frictional resistance is very small relatively), we will assume
that the whole pressure is producing friction.

(60) And, employing the ordinary value of journal friction, viz.,
0 07 of the weight, we have 5671bs. x 0’07 = 39*691bs. resistance in the
journals ; and allowing the crank leverage ab (Fig. 6) to be equal to the
leverage of the engine crank = 6in., and the diameter of the plane

39.59

spindle to be l jin., we have 6 — 1*5 = 4 times ; and - — — = 9*921bs.

power needed at the pin e of Fig. 6, coincident with the engine crank-pin,
to overcome the resistance in the journals.

(61) Now, as the radius leverage of the engine power is only 6in.
for a 12-inch stroke, whereas the plane pressure on the wheel-rim has a
radius leverage of 4ft., the engine power will require to be as much
greater than the plane pressure as its crank leverage is less ; so that
4ft. -r- 0*5ft. = 8 times ; and 53‘251bs. x 8 = 4261bs., to which we add
the 9'921bs. of journal resistance, making the total resistance at the
engine crank 435'921bs. ; and, making the ordinary allowance of 1th of
the piston pressure for power consumed in the engine, we have for total
actual piston pressure needed, 435*92 + 62*3 = say 500'01bs. piston#
pressure.

(62) Then, taking steam at 201bs. effective pressure above the
atmospheric pressure per square inch of piston .area, we have

5001bs. resistance „ . , ...

= 25 square inches area of piston.

201bs. steam

OF GREAT BRITAIN,

(63) The stroke of the piston being 12in., we have in each stroke
a consumption of 0T73 cubic foot of steam, which is equal to 0'346 cubic
foot for each full turn of the crank ; and as the relative volume of steam
at 20 + 15 = 351bB. pressure is 765 to 1 for the water it was formed
from, we have from every cubic foot of water evaporated steam for
2211 turns of the wheel ; which, supposing the wheel were running on
a path that allowed no slip, would, at one turn per second, give a
distance of 10‘52 miles in 3685 minutes = 0614 hour; and, as
1 cubic foot of water evaporated per hour is the value of 1 horse-power

• , 60 minutes , „ ,

nominal, we require here - — . - = l-63 horse-power m engine

36-85 minutes

To evaporate 1 cubic foot of water, the ordinary estimate allows
5>lbs. of coke ; but as a cubic foot of water weighs 621bs., and as the
boiler that evaporates 1 cubic foot of water in 36'85 minutes cannot be
a small one, it is clear that the motive power cannot be steam produced
in the ordinary manner ; and we have employed steam pressure here
merely as a standard index of the power required.

Chapter VIII.

(64) We shall now endeavour to determine the value of the
pressure of the planes in the form shown in Fig. 9, in which the plane

Fig. ».

does not rotate round its own axis, but simply oscillates on an arc of say
25", to give Y pressure in its passage from a to a"; the area of

AERONAUTICAL society

X pressure being horizontal at both the points a and a", unless when
otherwise purposely sloped to get a rising or a falling resultant, by the
slight canting of the platform inside, or of the framing that supports the
eccentric ring.

(65) The axes of the planes when rotating with Y motion will
describe a curve, which will have its point of rest at a" (Fig. 4) as in the
curve (Fig. 2) for the form of wheel (Fig. 1) ; but, supposing the planes
able to exert the required Y power, and to travel in the path of their
inclination, so as to form the curve thereby, we might expect to find the
curve flatter than shown in Fig. 2, and the distance h"a" consequently
greater.

(66) Were the planes kept uniformly horizontal, and the wheel to
run upon a rail, the curve would be the same as for the form (Fig. 1), so
long as the rail was run upon ; but the planes thus horizontal could
exert no Y pressure, and it is clear that the rising and the falling curves
would be in opposition.

(67) While upon the rail, the mean angle h"aa" (Fig. 4) for the
curve, would be about 574° (Par- 32) the cosine value of which is about
0*8435 ; but, as the planes are here for the moment assumed to be
uniformly horizontal, so as to be of the full value 1 ’0 in resistance to X,
we have the 0*8435 value, relative, not to area of X displacement as in
form Fig. 1 for the curved resultant ada" (Fig. 2), but to the rate of
velocity in shifting on to fresh air, represented by the decreasing
successive spaces vb, b"c, d'd, d"e, &c. (Fig. 4), in successive equal spaces
of time, which are best represented by the spaces which separate the
axes of the planes on the wheel’s circumference. But we have the value
of the resistance to X in this 0*8435 measure only while the wheel is
running along the rail ; and if, on an air path, we can increase the

Y velocity beyond the velocity of rotation, and thereby make the inclined
planes shift on to new air more rapidly, we may raise the mean
X resistance pearer to the full value 1*0.

(68) The arc of oscillation measures say 25°; the mean of this for
the curve aa" is 124°, and 574° + 124° — ?0° for the angle which, with
a longer Y base, is to take the place of the angle h"aa", with the shorter

Y base hi' a". For convenience, in treating this arbitrary angle, we will
employ the letters belonging to the angles of Fig. 4.

Sine hi' a". Cosine hi' a. Cotangent gw.

h"aa" = 70° 0*98969 0*34202 0*3639

0*34202

0*93969

0*3689.

OF OBEAt BRITAIW.

And, as at this angle, the sine h"a'‘ in the time of the plane’s descent
from a to a", represents the resistance of the plane to X, we have h"a
representing the pressure which would give Y motion were the plane
actually moving in the line of the tabular resultant apa" with a uniform
slope of 70° vertical angle, coincident with the angle of the resultant.

(69) But the mean angle giving Y pressure is only 12£° horizontal
angle, say aa"h", equal 774° vertical angle, say h"aa and the sine and
cosine of this latter angle are —

Sine . h"a" = 0 '97629

Cosine . h"a = 0-21643

Cotangent., gw = 0-22169
Tangent ... yx = 4'61

So that the Y pressure cannot be in greater proportion than 0-21643 to
0-97629 for the X pressure; and as the sine h"a" of the mean angle is
0 97629 to TO for the actual Y length of the plane, we make the

Y length of the plane when horizontal equal to the cosecant of the 774*
vertical angle, that is, 1 '02427ft. in place of 1ft. ; and thereby have the
sine h“a" = 0 97629 in the Table, representing 1ft. actual; so that, as
the tangent gw bears the same proportion to the radius a!' a that h"a bears
to h"a", if h"a" the sine = 0 '97629 be taken to represent the tabular
radius 1-0 for X pressure, K'a the cosine will represent the cotangent
0-22169 part of 1-0 for Y pressure ; consequently, if the X pressure be
lib., the Y pressure will be 0"221691b.

(70) This refers to displacement resistance. The velocity of

rotation on the rail gives the curve ada" for the mean angle of

about 574°, with the K'a" sine value of 0"843, and the K'a cosine value

of 0 537 ; and sine 0 843 , „

. A -o = T57 ratio = tangent yx,
cosine 0-537 6 9

so that, as K'a is of the constant value of 8ft. for the wheel’s diameter,

measured between the opposite axes of the planes, we have T57 x 8

= 12-56ft. for K'a", the distance run upon the rail

As, however, the 12j6 mean Y angle increases the mean angle of

the curve to 70°, we have for 70°

sine 0-9396 _

cosine 0 342 ° 9 ’

and 2747 x 8 = 21-976, say 22ft., for K’a", the length that would be

travelled in a half-turn of the wheel upon the air path free of the rail,

were the Y pressure in sufficient force, and to take full effect in producing

Y motion.

(71) We shall now ascertain the value of the air resistance to Y,

aeronautical society

and assume that the velocity of rotation round the axis of the wheel is
at the rate of one full turn per second ; the valne of the mean of V 2 for X
will therefore, as before (par. 15), give 17‘58ft. for V; and the air
resistance to X at this mean rate will be 0 5021b. per square foot of
projected area, perpendicular to the direction of the motion (par. 18) ;
and, as we make the actual length of the plane 1 ‘02427ft., we have the
mean sine hi' a!' equal to 1‘0 for the area of displacement in the descent
from a to a" ; then, per foot of plane,

0‘5021b. x 0‘22169 = 0‘1 11281b. proportionate Y pressure.

(72) We have assumed 180 square feet as the whole area of the
planes, and, as Y pressure is had only on the falling curve aa" when
the drag due to edge resistance is neglected, that is, on one-half of the
area for the whole curve, we have

0 1 11 281b. x 90ft. = 10‘0151bs. constant mean Y pressure.

(78) The edge resistance of the planes would be due here to
a velocity, roughly, of about 44 — 2513 = 18‘87ft. difference + 35 46ft.
of par. 38, — 54‘33ft., which wou(d give a pressure of 4‘6651bs. per
square foot of area perpendicular to the direction of the motion ; and, as
for the 0‘0417 square foot of edge per foot of plane (par. 39), we have
0'0417 x 180 = 7‘5 square feet, and 7‘5 x 4‘665 = 34‘981bs. resistance,
for which there is only 10‘0151bs. Y power.

(74) It is clear, therefore, that the Y pressure of the planes, when
oscillating on a mean arc of 12^°, is insufficient to propel the wheel ;
and if the angles of inclination given to the planes in the rear or rising
side of the wheel correspond, because of the mechanical difficulty to have
it otherwise, to the angles in the falling or propelling side, the upper face
resistance on the rear planes will neutralize the X effort of the front
planes more and more as the Y distance hh"a" for one turn is shortened.

(7 5) Greater velocity of rotation would develop more Y pressure,
but the plane edge resistance would develop with it, and in this edge
resistance of the rotating planes do we see one great disadvantage to the
wheel form.

(76) It is evident, moreover, that the eccentric or other gearing
that can vary the angle of the planes in the rising curve so as to travel
in the fine of a curved path of varying Y velocity, though it must
necessarily be of a simple nature and of light construction, presents
considerable difficulties, more especially when, to have the wheel under
perfect control, the simple mechanism must be capable of bringing all
the planes to slope uniformly in any direction ; ' horizontal for quiet
floating ; vertical for arresting motion ; or inclined up or down to the
horizon.

OF G&3SAT BRITAIN.

Chapter IX.

(77) In Fig. 10 is shown an arrangement of eccentric rods, by means

Fig. 10.

of which the face of the wing planes may be horizontal at both top and
bottom of the wheel, the Y propelling force being got by means of the
variable angles of inclination given as shown in the descent from a to k.

The floats are formed, say, of thin veneer, to which silk or other
cloth fabric may be glued.

The V cranks, placed in the planes as shown in Fig. 8, are connected
together by means of a series of light rods, each of which has a few spiral
turns in the middle of its length for elasticity.

To one of the plane V cranks thus connected, say to the crank Z,
one end of a stiff rod is hinged ; the other end K is weighted, and at an
intermediate point in the length, the rod works on the pin B of the
oscillating crank A B.

The crank A B is made to oscillate in a determinate manner by
connection with the motive power that causes the wheel to rotate ; and

AERONAUTICAL SOCIETY

the oscillation is needed to allow the end Z to occupy the successive
positions f, h", i, j, Jc, l, &c.

Only one oscillating rod can be got to work, and this single rod is
all there is to keep the system of light spiral rods in form.

The mean angle of the planes in the descent from a to h in Fig. 10
is greater than we have named for Fig. 9.

In Fig. 11 we show the planes inclined as in Fig. 10, on a curve

Fig. 11.

equal in length to the circumference of the wheel only, as in Fig. 2 ; so
that, at the successive points, Fig. 1 1 exhibits the variable divergence of
the angles of inclination of the planes from the line of the curved path,
while the wheel is running upon the ground.

Assuming the planes have power to float the wheel, and to give

Y velocity greater than when running on the ground, the angles of
inclination of the planes will more closely approximate to the line
of the curve, the flatter the curve becomes by the extension of the

Y distance LM.

The plane N (Fig. 11) in rising will tend to depress the wheel, but
the upward motion from L to IV is slow, and the plane quickly assumes
an angle closely approximating to the line of the curve on rising
beyond N.

The wing-planes between the wheels (Fig. 8) may be of the hollow
form shown in Fig. 10, but the extension outside of the wheels may be
of a form possessing greater elasticity.

(78) It is apparent to sight that the sum of the circular lengths of
the eight rods which connect together the V cranks of the planes is only
a very little less than the circumference of the circle which passes
through the axes of the planes ; and that if the axes of the planes be free
to move a very short distance in toward the axis A , the length of the
circle thus contracted may be brought to equality with the circular value
of the sum of the lengths of the connecting-rods, the polygon formed by

OF GREAT BRITAIN.

which will then be free to change from its general oval form to a form
nearer a circle, if not prevented by the oscillating crank -rod KZ ; and in
this change of form the V cranks of the planes will be allowed, approxi¬
mately, to take the same vertical direction all the more readily if the
planes be set upon the axes so as to give a slight excess of pressure on
the rearward part of their surface ; and with the planes thus at liberty
to assume a general horizontal direction, the wheel may be quietly
floated at the will of the person on the platform.

The means employed to move the axes of the planes the very short
distance inward are not shown in the Figures ; it is evident, however,
that those means would require connection with the oscillating crank of
the main rod KZ, and be capable of being thrown into and out of gear
in the short time required to move a simple hand lever.

Chapter X.

(79) As the edge resistance of the planes rotating round a centre
is greatly increased by the velocity of rotation, we shall now speak of
planes which shall only oscillate on hinges in the manner of birds’ wings.

Let the weight borne be 2’51bs. per square foot of wing.

According to Morin, the velocity required to give 2’51bs. resistance
in air is — sq. ft.

Area (-00737 + -0016 V*)=R, and 1 ( 00737 + -0016 x 39’522) = 2’51bs.

Then if we represent this 2’51bs. resistance by a column of air at rest
weighing 2’51bs., this column of the given weight, if put in motion from
a state of rest by pressure increasing beyond the pressure that it
balances, would offer the resistance of its inertia increasingly from zero ;
and, as we are treating of the resistance of air, with a plane of 1 sq. foot
area, and weighing 2’51bs., it is clear that as the air resistance due to
a velocity of 39 '52ft. per second would balance the plane possessed of
that weight, so as to make the motion uniform, we would have the
weight sustained at a given level in the air, by giving the velocity to
wing-planes oscillating upon hinges on the weight.

39’52

The velocity of 39’52ft. per second is in the ratio of g =

1’228 to 1 for the velocity due to natural gravity for 1 second, or would
take 1’228 seconds to develop naturally, so that as the elements of
natural gravity form the standard by which to determine the value of
weight in motion generally, and as we take the rate per second as the

AERONAUTICAL SOCIETY

unit standard, and further, as we have to consider the winged body as
tending at any point of its assumed horizontal flight to fall earthward
from a horizontal level representing, as regards earthward motion, a line
of rest, we employ the force of gravity of the given weight for one
second of time t (the velocity generated in one second in space free from
air is g = 32ift., irrespective of the value of the weight!, and have in

g * t = 32-18

3218

the force of gravity equal to the weight

simply, and equivalent to the force of inertia resisting it, which thereby

defines the value which we call weight. And when the motion - is less

than for natural gravity, it is obvious that the weight being urged with
less speed-force, its inertia force is less developed, and, when the motion
takes place in air, with the given weight centred say in the axis of the
hinge on which the wing is made to work, and the earthward motion
that would otherwise be in the weight is substituted by the motion given
to the wing, so that the weight is sustained and the wing alone moves,
it is evident that the air must now be made to sustain the weight, by
means of the pressure equivalent to weight developed in it by the wing-
strokes, and as the 39-52ft. velocity gives 2'51bs. resistance, represented
by an R column of that weight at rest, any less velocity will give a
column of R resistance proportionately lighter, so that as the force of
inertia of the air is the sustaining force, the force to sustain the given
251bs. weight mu3t be got in the one second of time, from as many of
the lighter R columns as will form an equivalent to the standard single
column, and this can be got only by shifting the plane forward
horizontally while the wing is beating vertically.

(80) As g is the standard value of the force of gravity for one second,

. v

and as the time in the expression - is one second, we are here free to

simplify the equation — x -, thus — x v = Mv for 1 second. Were

the times t in the several cases unequal, we would require to employ the
full equation, as the forces developed are proportional to the rates of
motion for a given time.

Were the weight W in space free of air, its natural force of

v 39-52

gravity would take, as before observed, - = ■ Q = l-228 seconds to

y 32 * 18

attain the velocity that in air would develop 2-51bs. resistance, and as
we assume W to weigh 2'51bs., this air resistance would simply balance
it ; but as v when thus employed in developing air resistance would be

OF GREAT BRITAIN.

the actual rate per second, without reference to the time that natural
gravitation would require to develop it, it is clear that the force here
performing in one second the work that requires 1 ’228 seconds in natural
gravitation, it exceeds the natural force of gravity, thus —

" x ^ = 3 071bs. force, which is 0'571b. in excess of the

32-18 1

natural force.

v 32-18

As before observed, were - = — — — , the force — which in natural

t 1

gravitation may be regarded as either the force of inertia in the weight,
or the force of attraction drawing it earthward — is the weight simply,
and for lower velocities per second we have the force developed propor¬
tionally less.

(81) Now we will, for the moment, assume that in giving the wing
while beating 7 shifts horizontally on to fresh air at rest, we get 7 times
the support, then,

39-52* = ~ = 223 = F*, and ^223 = 14 933ft. = V.
sq. ft.

Then, TO ('00737 + '0016 x 223) = 0 ‘3 6 41b. air resistance, which we
represent as being balanced by a column of air weighing 0-3641b., which
we term w, and employ it in the equation for the force of inertia to get
the resistance of inertia which this weight w would oppose to v at the
0*304

14-933 rate. — * x 14 933 = 0-1691b. inertia force of resistance to

32*18

the pressure of the wing ; and as we assumed 7 horizontal shifts, which

oives 7 columns of resistance, we have 0"169 x 7 = l'1831bs., which is

2-5

less than half the sustaining resistance wanted, so that — — =2 "11 times,

and 7 shifts x 2'11 — 14 77 shifts needed at the given 14-933ft. rate of
velocity, to sustain the 2'51bs. weight in horizontal flight.

Assuming the wing to be 1ft. broad, 1 4'77 shifts per second
would require the weight to be propelled horizontally at the rate of
10 miles an hour upon the ground before it could be floated off, supposing
the wing mean-velocity to be no greater than 14'933ft. per second.

Assuming the wing to be 10ft. long, the centre of pressure to
be say 6ft. from the hinge, and the length of wing stroke measured at

14*933

the centre of pressure to be 5ft., this would give — - — = 2"987 full

strokes per second, or about 180 strokes per minute.

(82) Doubling the number of wings, and making each only 6in.
broad, the length and velocity of stroke being as before, 14"77 shifts

AERONAUTICAL SOCIETY

would be got in half the time, and as we here have the air
resistance per unit of surface the same as before, we have the inertia
resistance of the double number of columns of air support for one din.
breadth in one second of time, the same as the resistance for the
lft. breadth shifting the same horizontal distance in one second : thus,
0 "36 41b. air resistance for 1 square foot, with breadth 1ft., at 14 ‘93 3ft.

velocity per second ; then - = 0 ‘1821b. for £ square foot, with

“ 0*182

breadth 0.5ft., at the same velocity; Q x 14*933 = 0*084371b.

32*18

inertia force of weight representing the pressure.

Twice the number of shifts in one second gives 14*^7 X 2 = 29‘54
shifts, and 0*08437 x 29 54 = 2‘51bs. aggregate inertia force for
one second, so that as there are two wings now in place of one, we have
2 ‘5 x 2 = 51bs. inertia force per square foot of area.

(83) If we keep the number of wings, the velocity of stroke, and
the area of each wing, the same as at first, but extend the length so that
the breadth shall be only 0‘5ft., we shall have, as in the last case,
2954 shifts in one second, and shall thereby similarly have 5‘Olbs.
inertia resistance for support when the horizontal propulsion is at the
rate of 10 miles an hour, or shall have inertia resistance equal to the
weight when the rate is only 5 miles an hour.

A wing extended thus, however, and making beats equivalent to a
mean velocity of 14‘933ft. per second, would be unwieldy; but, as the
10-mile rate gives 51bs. support per square foot area, the velocity of the.
wing-stroke would be proportionately less than 14‘933ft. per second, to
produce resistance to float 2‘51bs. off the ground. Moreover, when
afloat, and free from the resistance to rolling on the ground, a greater
horizontal velocity than 10 miles an hour would be attainable, giving
more rapid shifts of the wing breadth on to new air at rest, so that the
velocity of the wing-strokes may be proportionately still further reduced ;
and this implies a reduction of the .motive power.

(84) In Fig. 13, with a view merely to illustrate the principles
concerned, we show three wings of short length taking the place of
one wing of long unwieldy length, the breadth being the same, and the
united area of the three being equal to the area of the one.

While on the ground *the horizontal motion that gives the wing
the extended bed of air for support may be got by means of lightly-
framed wheels ; but, when sufficient air support is got to float the
weight, the angle of the wings in the sloping of the breadth in the

OF GREAT BRITAIN.

manner already described will give the forward impulse ; and, in the
upstroke the wing with the angle reversed will rise free from pressure
on the upper face.

Figs. 12 and 13 give general expression to the manner in which
the wings may be worked. It is a simple matter to compute the motive
power that would be required at the crank axle to work the wings
against the given air resistance.

Fig. 12.

Fig. IS.

(85) Now, were the wings few in number, so that in shifting hori¬
zontally they might always be coming upon air not previously disturbed,
we might get the full effect of the inertia of the bed of air which is
travelled on ; whereas when the wings are many, the rearward wings
would find the air they came upon in a disturbed state, more especially

AERONAUTICAL 80CIETY

at the lower horizontal speeds wheD gathering velocity to rise from off
the ground. Were they ranged in horizontal series, so as to make their
up and down strokes in unison, the leading wings alone would make
each successive down-stroke in new air. In .the up-stroke the wings
might be inclined so as to rise with front edge resistance only ; but,
until velocity of flight was reached sufficient to give a bed of air support
so great that the inertia of the weight of this bed would sustain the
winged body so as to float it, part of the force of the down-stroke would
be expended in giving motion to the air, and the rear wings would be
beating upon air which was in confused motion.

Were the wings ranged with their hinge axes on each side in one
horizontal line, but the crank e of each single set coupled as in Fig. IS,
so keyed that the tips of each series might form the curve shown in
Fig. 12, we would then have the rearward wings following in the path
of the preceding wings, with a result similar in kind though not quite in
degree to that which would attend the employment of a single plane,
equal in area to the sum of the wing area it represented, were this single
plane made to oscillate in the wave-like manner represented by the
curve. But as each wing of the series has to make a given number of
strokes per second to get the air resistance It already spoken of, we
would have as many wave-like curves in the distance of flight per second
as there are strokes in a second ; so that the curve of Fig. 1 2 relates
merely to the placing of the cranks on the motive power driving shaft
to produce continuous in place of maximum and minimum effect ; and
it is clear that the velocity of flight must be great to give an air-bed so
extended in the direction of the flight that the leading wings, with their
given weight of pressure, have not force to give appreciable motion
earthward to the air that has yet to receive the weight of pressure of the
succeeding or rearward wings.

Chapter XI.

(86) Fig. 14 shows the end view of the winged wheel before
described, but with another form of gearing for giving a variable slope
to the rotating planes, with means to bring them at will to one uniform
slope for quiet floating. In this case the axle of the wheel is not cut,
nor are the axles of the planes V cranked as in the preceding instances.

All the gearing is inside between the wheels that carry the planes.
To balance the weight of the gearing one-half of the planes are connected
at one ring, and the remaining half at the other ring.

OF GREAT BRITAIN.

Fig. 14.

On each plane r.xle there is placed one grooved pulley a, of say
about 9in. diameter ; an endless chain bb (to be hereafter spoken of)
works round this pulley and one lettered c on the wheel axle, so that,
for the six planes d, e, f; g, h, i, geared at the near ring in the figure,
there are six pulleys c close set together on the wheel axle, each free to
move independent of the others, and each oscillated by an independent
cogged lever j, which is put in motion by a connecting-rod 1c, in gear
with an eccentric l, which is worked by connection with the motive
power engine.

The clump of pulleys on the wheel axle are of uniform diameter,
the same as that of the single pulleys on the plane axle. Were the
pulleys c kept fixed, the planes of the pulleys a would be maintained at
one constant slope, say horizontal. They are wanted to be horizontal
only at the top and bottom of the wheel, and the oscillation of the

AERONA.TrriCAL SOCIETY

pulleys c is for the purpose of giving the plane that variable inclination
that shall produce the motion of flight.

(87) There is an eccentric l for each pulley c, and cogged lever j ;
and these eccentrics are so set upon the shaft — in the manner to be
presently described — that one-half the number is oscillating the planes on
the rising side, while the other half is oscillating those on the descending
side. For clearness we show only one set of eccentric l, cogged lever j,
and cogged quadrant to.

The full lined forms j, to, and l, show the position for the
plane at n ; the dotted forms show the position for the plane at o ; and
the mean of those two positions gives the plane at p or q.

' The pulleys c are close to the inner face of the wheel ring, and are
fixed on hollow tubes, concentric with the wheel axle, and of different
diameters, so that the larger easily slide round upon the smaller.

At one end of each tube a pulley c is fixed, the inner tubes
severally project at the other end beyond the outer tubes, sufficiently to
receive on each projected end a light cogged quadrant m, and with this
quadrant is the cogged lever.;' in gear.

The eccentrics l have a narrow seat upon the shaft, but their
work is light, and instead of being keyed to the shaft they are driven by
a small shallow cog which projects from the shaft, and which has a play
of one-half the circumference, from a to b in the recess cut in one end of
the eccentric boss, as shown in Figs. 16 and 17.

According to the direction of the motion, this cog will catch at
one end or other of this recess, and when the motion is stopped, and it
is desired to bring all the crank levers j and quadrants to to the mean
position, so as to get all the planes say horizontal, the eccentrics are slid
round in the same direction they had before been driven in, the cog is
thereby left behind somewhere in the recess, at a distance from the end
it had been pressing against determined by the position of the eccentric
when the axle motion ceased.

To work the eccentric thus free, a light thin ring may be attached
to the outer point of the eccentric, so as to be concentric with the axle ;
on this ring are two small projections on opposite sides of the diameter
as shown. Then, a crank lever r, working freely on the axle, has
attached to the crank limb a hanger s, which on the motion of the hand-
bar r is raised to rub on the edges of all the thin rings, so that, on the
continued motion of the hand-bar round to u, all the projections between
v and v) of the several rings are carried up to w, and this will cause all
the planes to be sloping uniformly.

Fig. le.

Or GREAT BRITAIN,

Fig. 15.

U' 1 / /

\ \

I )

,A ( 1

A V \ \ \

j f

AERONAUTICAL SOCIETY

The endless chains bb must have a reliable hold upon the pulleys ;
this might be got by means of long links and of flats to correspond in the
pulley groove. It may also be got by casting small iron balls between
the eyes of links at close intervals ; these balls to lie half bedded in
corresponding hollows in the groove.

(88) The force required in the chains to regulate the inclination of
the planes is very small, but though the gearing be made correspondingly
light, the aggregate weight will be a burden upon the sustaining power
of the planes ; and the gearing here described is to be regarded (equally
with the wheel form of the plane-frame) only as suggestive data from
which something simpler may be devised ; and with a view to lightness,
thin sheet steel, in the room of the veneer mentioned in par. 77, might
be employed, as spindles the full length of the planes might thereby be
dispensed with.

The slot in the arm of the cogged lever is to allow of the arc of
oscillation being regulated to suit the conditions of flight ; a very simple
addition would enable the arc to be regulated when in motion.

Fig. 1 5 show* the angles the planes would form with their path in
a cycloidal curve.

OT GREAT BRITAIN1,

FALLING PLANES.

Chapter XII.

(89) Suppose a thin plane, square, and of 1 square foot area, at rest
in air, as at a in Fig. 18. If allowed to fall freely earthward, its velocity

Fig. 18.

of descent will be accelerated variably until the rate of 25ft. per second
is reached, beyond which point, in air of ordinary density, the rate will
continue constant at 25ft., because at that rate of velocity the plane
meets with resistance equal to its displacing pressure, and the force of
inertia developed in the resistance which the air offers to displacement
is equal to the force developed in the weight of the plane in the motion
of its fall.

The fall required by gravitation close to earth to generate 25ft.
velocity per second is 971ft., equal to ad in Fig. 18 ; and we employ this
height of fall as a standard by which to determine the relative values of
different velocities.

The force of inertia of lib. falling with the velocity of 26ft. per

second is

lib.

25ft.

= 077671b., and, though the pressure is equal

oZ lo a 36C •

to lib., the sustaining resistance of the air displaced under this pressure
is only 077671b. Were the sustaining resistance lib. equal to the
pressure, then the motion of the plane would be arrested.

(90) We will now suppose that the plane is possessed of horizontal or
Y force to carry it along from a to & at the uniform rate of 25ft. per

AERONAUTICAL 80CIETT

second, so that it makes 25 cl^ar shifts on to air at rest in that distance
and time.

1 86C.

The time per shift is = 0-04 second ; but the sustaining force

of inertia required to place the falls x and X on equal terms as regards
0 77671b.

support is - - — - 0 0311b.

(91) Were the velocity which is generated in a fall from zero in
0'04 second of time to develop air resistance equal to the falling force
in the weight of plane, we would have the resisted fall x for the given
plane and T distance equal to only 25 times this first-shift fall ; but as
the sustaining force on the Y path is not the imposed pressure, but the
inertia of the air displaced, or the resistance which it offers to any
acceleration of the velocity to which the pressure is due, the plane, if
assumed to fall from zero or a state of rest at a, would have to fall at a
variably accelerated rate a longer time than 0'04 second to give pressure
that would yield the requisite 0-0311b. resistance to acceleration referred
to above.

When the plane falls in a purely vertical direction X, the resistance
of the opposing single column of air is able to balance the force in the
falling plane so as to produce uniform motion, only when the velocity
rises to 25ft. per second, and then requires this velocity to be maintained
in the plane, which is consequently carried at that rate earthward ; and
we seek to lessen this inconvenient velocity by carrying the plane on a
Y path over the surface of a greater body of air, thereby extending the
area of support.

Then, in the case of a plane making a free fall in air from zero, in

place of one column of one second’s length, we have 25 columns of — — '

mean length ; and as the weight of air that forms these minor columns
is come upon at rest, with the velocity of the falling plane increasing,
but with the rate of acceleration decreasing as the resistance develops,
we have the force of inertia in each succeeding column variably greater
than in the last preceding ; but in the sum of the resistances of the series
of minor columns we have the sustaining resistance of the air equal to
the sustaining resistance of the long single column for a purely vertical
fall. The decrease in the rate of acceleration as the falling plane
develops increasing resistance in the opposing air when shifted F-ward
cannot well be stated in simple terms, but we may get the result wanted,
approximately, in ratio form, thus : —

OF GREAT BRITAIN.

The force of inertia in lib. falling at the rate of 25ft. per second is,

as before observed, 0 '77671b., and

0-7767

= 0‘0311b. constant force of

inertia on the Y path of 25 shifts of place, and a velocity of about 8'3ft.
per second will give this.

The natural fall by gravity in space, to generate this velocity is

i A-rr. , 9 71ft. for 25ft. velocity „
l'07ft., and - — - ■ - - = 9 0 ratio, or

252

625

107

8'32 68'89

= 90.

(92) We will now assume that the square plane #f 1 square foot
area weighs 21bs., and will consider the effect of the 25 Y shifts under
the altered conditions.

To develop air resistance equal to 21bs. per square foot of plane, we
require a velocity of 35 "35ft. per second, and the force of inertia of this
weight at that velocity is 2-1951bs. greater than the simple weight of the
plane, because the velocity is greater than the rate of acceleration per

second of natural gravitation ; and — — - = 0"08781b. constant force on

the Y path. The velocity of 1 1 95ft. per second will give this, and the
relative fall in space is 2 22ft ; then

9-71

2-22

= 4 "37 ratio; or

252

11-95*

625

142^8

4-37.

In a free fall in space near earth, 1 1 second nearly would be required to
give 35 35ft. velocity, and this time for that velocity, in space, would be
the same for lib. as for 21 bs. The time of Y for ah is 1 second, and the
velocities named are the rates per second, and we employ the 25ft. rate
as our standard of comparison ; hence the ratio last determined.

(93) If we now take a plane measuring 0"5ft. in the Y direction,
and of 0 5 square foot area, and weighing lib., bo as to represent one-half
of the last-named plane of 21bs. weight, and urge it forward so as to
travel the Y distance ai in 1 second of time, we will have 50 Y shifts.

and — 1 09751b. for the given half area; and - = 0-021951b.

constant force on the Y path. The velocity required to give this on i sq. ft.
is 9'4ft. per second ; the fall in space due to this velocity is l"37ft. ; and

= 7 088 ratio ; or = 7"088
1 ‘ 37 88*36

(94) Similarly with the square plane of 1 square foot area, when

halved, and the halves separately moved from a to b. Thus, for lib. per

square foot, the force of inertia is 0.7761b. as before determined, and

0-776 0-388

— — - = 0'3881b. for the given half area, and — — = 0 00771b. constant
Z 50

AERONAUTICAL SOCIETY

force on \ sq. ft. The velocity here required is about 6'55ft. per second ;

9'71 625

the fall in space 0 67ft. ; and — — = 14 5 ratio ; or = 14'5.

O' 67 43

(95) Keeping the Y length 0-5ft. as in the last two cases, but
making the lateral length 2ft., to get 1 square foot area, we have here
50 Y shifts in the distance ab ; and for a weight of lib. have
0776

■gQ— — 0*01551b. constant force on the y path. But as we have twice

the area of support in the distance ab by reason of the lateral extension,
it is evident that a velocity which gives half the inertia force here named
0 -0155

will suffice, — - — = 0 007751b. For this on 1 ft. sq. there is required

a velocity of 51ft. per second, with a fall in space of 0‘404ft. ; and

9-71 . 625

- = 24 ratio ; or - = 24*0.

0-404 ’ 26.01

(96) Keeping the weight lib., and the area 1 square foot, but
making the Y length only 0-33ft., with the lateral length 3ft., we get

— — = 75 shifts of the plane in the distance ab for 1 second. Then
0*7767

— — — = 0-01031b. constant force of inertia in the T path.

75 r

As the area of support however on the Y path ab is three times the

area travelled over by the plane which measures l'O x l'O = 1"0 sq. ft.,

a velocity which gives one-third of the above force will sustain the plane

so as to make that one-third velocity uniform.

Then — - — — = 0 003431b. force of inertia in the velocity required,

which is at the rate of 3 7ft. per second. The gravitation fall in space
co give this velocity is 0 2127ft., and

9-71

0-2127

45-6 ratio ;

625

13-69

45-6.

We will now show the relative values of the ratios.

Ratios . 9 4-37 7‘088 14-5 24 45~6

Relative values... 1 485 787 T63 2 66 5"0

greater fall x. less fall x.

OF GREAT BRITAIN.

FLIGHT OF BIRDS

Chapter XIII.

(971 We shall now consider the means by which the horizontal
impulse Y can be produced with only the air to act upon as an abutment.

A plane in motion, with its surface perpendicular to the direction of
motion, compresses the air beneath it, so that the air driven out of place
escapes uniformly at the edges all round.

When the plane is inclined as a b
(Fig. 1 9), and let fall earthward in the
direction X, the tendency is for the
air to roll up the face towards the
upper edge a until the X velocity pres¬
sure develops inertia resistance in the
air sufficient sensibly to sustain the
weight of the plane ; the plane then,
thus supported, will tend to glide
F-ward ; but upon the amount of
edge resistance at b will depend the precise value of the velocity Y.

(98) In the first wing-strokes of a bird when commencing flight
the air will give support equal only to the inertia resistance due to the
velocity of displacement of the weight of air displaced.

A heavy bird, when free to choose the direction, rises against
the wind when commencing flight, to get the sustaining force of the wind
in aid of its own efforts ; or lets itself drop slanting from a perch ; or
runs if on the ground, to bear its wings along the surface of a greater
weight of air than it could put in motion by a wing-stroke if stationary ;
its wings when thus running labouring more than when fairly up in air
with the Y velocity great.

Fig. 20.

Fig. 19.

\ '

AERONAUTICAL SOCIETT

(99) The impelling force is exerted in the down-stroke a to 5
(Fig. 20) ; and, though the wing has to rise from b to e to make the
succeeding stroke, it rises free from resistance on its upper face.

Thus, let F be the forward impulse given by the down-stroke,
and M the motion of the rise to e for the succeeding down-stroke. Then
bd represents the Y distance travelled by the wing W in the rise ;
de represents the rise ; and — for convenience assuming the path of the
rise to be straight — Y and M are represented proportionately by y and
m for any point intermediate between b and e, the resultant of these two
forces being in the path be ; consequently, a particle of air caught at the
leading edge e' of the wing, and deflected into line with the upper face,
will not be further deflected, but will remain there until the rear edge of
the wing has passed.

(100) Then, as regards the pressure on the lower face, we have the
air supporting the wing against the X tendency to gravitate, as in the
down-stroke ; and as the wing by reason of its upward M motion is
receding from the pressure ; and as the force of inertia of the weight of
body supported by the wing is very small at the start in a new direction
.ST-ward ; and further as the body has acquired Y momentum in the
preceding down-stroke, we have the X tendency affecting very little in
the time of the up-stroke.

(10F The impulse Y, however, owing to the air resistance on the
surface perpendicular to the line of flight, will be weaker at e than when
starting from 6, and will consequently, when near e, make its shifts on
to new air less quickly ; and this slowness will allow the air near t to
acquire motion from the pressure, and therefore yield X-ward ; but as the
impulse Y developed in say the half-time cb, is assumed to be equal to
the force needed by the whole-time cd, the mean for cd is sufficient to
carry the wing to e on a level with a.

It is evident, however, that with the force developed in eb and
acting by momentum only in bd, the body would have an upward
tendency in cb, and a sinking tendency in bd, were the angles bac and
bed equal. We must, therefore, suppose the time bd less than half the
time of a full stroke, and the time cb consequently more than half ; so
that the impulse Y may develop its force on a long resultant ab, and the
rise be on a short resultant be, in which, less time being allowed to rise
the given height de, the tendency of the air to yield by the slowing of
the Y impulse will be compensated by the quicker rate of the upward
motion M.

(102) The bigger sea-birds, such as the albatross, are seldom aeea

OF GREAT BRITAIN.

to flap their wings ; yet even in storms, they work their way to wind¬
ward ; they do so, however, not in a direct line, but on a path which is
a succession of varied curves, in which the weight of the bird is made to
act against the force of the wind upon the outstretched narrow wings, so
that the weight is floated. The resistance or force of the wind upon
these outstretched wings is the same in kind as the resistance upon
wings that strike the air ; and the difference lies only in the manner of
employing it.

The albatross has long narrow wings, with the leverage great,
measured from the joint at the body to the centre of pressure ; so that
when in flight with its motion Y, equal to its own visible velbcity plus
the velocity of the opposing wind, were it obliged to strike the air in the
manner of ordinary land-birds with broader and shorter wings, more
power would be required than it possesses to maintain itself for days
upon the wing in the face of the rudest gales. The albatross and other
similarly winged birds, therefore, in place of making a wing-stroke to
form a resultant ab (Fig. 20), let their whole weight descend with the
plane of their wings at the mean angle abc, and thereby develop the
force that will raise their whole weight on the rising resultant be ; and
this is what an ordinary land-bird in part does, in launching out from a
raised perch, to develop impulse Y.

Fig. 21.

(103) In Fig. 21 let ah represent the wing plane in the act of making
a down-stroke from h to </, and inclined to the Y direction at the
angle hfg ; let ab be the Y distance for the time taken to make the
stroke ; and let i and d be intermediate points in the plane.

AERONAUTICAL SOCIETY

Now it is evident that as the axis of oscillation in the body
of the bird travels forward on the line ab, the wing-plane travelling
with it and possessed of the same Y impulse, the tip h, which would
descend to g were the axis stationary, will be made to descend on the
resultant hf, and will reach f in the same time as a takes to reach b.

In like manner the points d and i will descend on their respective
resultants dc and ij ; and as the Y distances ec and lcj are uniform with
ab, it is obvious that if the inclination of the plane be uniformly
the angle hfg from tip to axis, there will be air resistance on the upper
face of the plane at the points d and * equal to the values of the
respective angles Idm and nio in Fig. 22, in which figure hba = hfg, is the

assumed uniform angle of the plane from tip to axis ; dm and to being
the continuation of the respective resultants db and ib — dc and ij of
Fig. 21 ; and dl and in being the lines of inclination uniformly parallel
to Kb or hf.

To do away with this resistance on the upper face, the plane
may at all points have the inclination of the resultants for these points ;
that is, if the angle at the tip be hba (Fig. 22), the angles at d and i may
be respectively mba and oba. But as we find the wing-feathers near the
body are curved so as to lie fair with the form of the rounded body when
the wings are closed, we have these feathers, where the wing-stroke is
weakest, resisting the tendency of the weight to gravitate by opposing to
it the upward pressure of the air on the lower face of their plane of
inclination. In a bird-wing the flexibility enables it to assume the
angles here indicated, according to the pressure caused by the wing-
stroke.

(104) The velocity A' may occur either in a direct fall earthward, or
in a wing-stroke. In the latter case it may be regarded simply as taking
place outside of the body that is being supported ; the wings, sustained
by the inertia of the body, developing upon their plane-surfaces in the
stroke, — the motion of which is distinct from any other motion that the

OF GREAT BRITAIN.

body may have, — the resistance that could otherwise be got only by body
and wings descending together, supposing the wings merely outstretched

If the wing area to support a given weight be reduced, the air
has less surface to act upon, and must be struck with higher velocity to
increase the resistance per unit of surface, and to develop quicker

Y velocity for quicker shifts on the Y path of support, to allow the extra
weight of body no time to take effect in putting the supporting air in
motion. And as quicker wing-strokes develop greater resistance on the
wing-planes, so as to compensate for deficiency of wing area, it follows
that, with a given area, a quicker stroke will at any time give greater

Y velocity.

(105) The centre of pressure on the wing varies with the form ; the
distance of the axis of oscillation, or hinge, from the centre of pressure
is the length of the leverage with which the pressure is acting.

In a bird the wing is worked by the alternate contraction and
extension of the muscles massed about the shoulders, and it is hard to
exhibit their action by lines merely ; we will therefore treat the question
as one of simple leverage.

Fig. 23.

In Fig. 23 let ab represent the body of the bird, looked at endwise ;
ac and bd the wings ; ce and df the extent of stroke ; g the centre of
pressure j and gh the arc it describes in the stroke.

Now, to work the wings mechanically, let ai and bj be two
short levers projected from the wing-planes at the axes a and b, so that
each wing with its respective lever acts as a bent lever ; then the length
of the lever ai relatively to the length of wing leverage ag determines
proportionately the force exerted at i to make the wing-stroke gh.

(106) When a bird with its wings oscillating rapidly is stationary
on a perch, or in the first of a start to rise from off the ground, the
developed force of inertia of the weight of wing in motion has to be
expended, at the end of every up or down stroke, as a drag on something
before the wing can be turned into the new direction.

AERONAUTICAL SOCIETY

Were the weight possessed of no area on which to develop
sensible air pressure, the motive power would have to absorb the inertia
force at every turn ; but as a bird-wing is possessed of great area in
proportion to it own weight, and as the air is compressed in the act of
displacement, and by reason of its elasticity reacts upon the wing when
the turn of the stroke is happening, the effort of the motive power has
little to do beyond giving the simple weight of the wing the required
velocity in the new direction ; and the apparent difficulty that a heavy
bird has in starting from the ground relates in its first slow Y velocity to
the want of area of air surface in the Y direction.

J. A.

CONCLUDING REMARKS.

In our customary review of the work of the past year
we cannot point to any special mark of definite success
relating to the actual performance of flight ; we are however
cognizant of the fact that a great number of earnest workers
are pursuing their favourite science with undiminished
vigour, and with an amount of perseverance which must
ultimately lead to a practical result. The papers now
published show but a small per-centage of the amount of
patient untiring work that is continually going on ; and their
perusal cannot fail to astonish any one who has not made
aerial navigation a study.

In referring especially to Mot and Shill’s “Aerial
Steamer” we are not unmindful of the various attempts in
course of progress by others ; but we consider their
machine, now nearly completed, to be the most determined
attempt at solving the problem that has yet taken place, and
therefore feel justified in calling special attention to it. The
apparatus consists of two of their patent steam engines
coupled together at right angles, with variable expansion
gear capable of cutting off the steam at any portion of the
stroke ; the pistons are each 2in. in diameter, with a 2in.
stroke, and working — it is said — up to about 4 horses’ power.
The total weight of the engines, generators, and lamps, all
complete, is under 501bs. The engines actuate four driving-

AERON AUTIOAIi SOCIETY

wheels lOin. diameter, and these wheels act by frictional
gearing on the periphery of two aeroplane- wheels 6ft. in
diameter. The aeroplane-wheels have each twelve light
wooden planes fitted to them somewhat like screw propellers,
but with this important difference, that the pitch is variable
at every portion of the revolution. The action of these
planes on the air is a perfect mechanical imitation of the
direction of a bird’s wing in the various positions that its
surface assumes during the action of flight, giving, as it does,
an upward and forward thrust continually, without any
downward force from air on any of the aeroplanes.

The • whole apparatus is placed upon wheels. It is
intended to run it round a pole fixed in the centre of a circle
of about 300ft. diameter. The theory is that the planes
acting as an aerial screw will give motion to the ground-
wheels, the friction upon which will decrease with each
revolution of the planes, until it eventually leaves the earth,
and will continue to traverse a circle in the air until steam is
expended, when it will descend as gradually as it rose.

It may be anticipated that the difficulties attendant
upon the attempt to make a model perform all that is
expected of a machine of more practicable size will present
obstacles here, only perhaps to be surmounted with time and
perseverance.

The engine, for instance, which would be at perfect
command in a machine designed for practical utility, must
here be unapproachable whilst the aeroplane-wheels are
revolving.

Again, the model must be proportionately very much
heavier than a real machine, also possess self-action, and
cannot have intelligent assistance to govern the angles at
which the planes severally aci.

It is certain, however, that should ascent be attained,
the most rapid progress must ensue through absence of

OF GREAT BRITAIN.

friction upon the ground ; and it is equally certain that if
this desideratum be obtained with the model, the most
encouraging results may be anticipated by the far more
effective action of a large machine.

One of the main objects of the Society is to organize,
and, as far as possible, direct the efforts of various inventors,
and prevent experimental repetitions. Much waste of energy
has taken place for want of a knowledge of what has already
been done, and a loss both of time and labour from two
persons attempting the same thing unkown to each other.
This is a constant occurrence, and there is consequently
much misdirected effort. In many cases plans are carried out
which have been tried and failed half a century ago, and
which would have been avoided if sufficient insight into the
subject had been acquired in the first place by the perusal
of our reports and the other published information to be
obtained if duly applied for.

It is simply astonishing to hear of people trying
year after year to drive elongated balloons, or gas-bags
somewhat of the form of a German sausage, with a car
underneath it, and a screw of course. This is generally the
first conceived project of any one commencing to think upon
the navigation of the air, and each one fancies himself the
happy possessor of the secret. Yet what a very small
amount of science is necessary in order to show its fallacy.
A balloon simply floating in the air with its car and occupants
is in a state of stable equilibrium. The centre of displacement
of the whole mass is less than half-way down between the
top of the balloon and the car, while the centre of gravity is
very near the car ; but of course both are in the same vertical
line, and the whole floats perfectly quiescent and upright.
The horizontally elongated balloon is much more difficult of
management even when only floating ; the centres of displace¬
ment and of gravity are brought much nearer together, and,

AERONAUTICAL SOCIETY

from want of stiffness in the gas-holder — and experimenters
should bear this in mind — the centre of displacement in a
sausage-shaped balloon is more easily disturbed than in any
other form. Take a spirit level and notice now difficult it is
to keep the bubble in the centre, and this is in a rigid
substance — glass. But we have seen sausage-shaped balloons
turning up on end very curiously, and the gas swaying from
one extremity to the other in a very uncomfortable manner.
And if all this takes place when merely floating, how much
more so when an effort is made to drive , not in a line with
-the centre of displacement, but, as it is in all cases attempted,
very near the centre of gravity? It is something like a boy
tying his string to the bottom of his kite instead of to tfce
line of the centre of resistance. We make these remarks in
order to illustrate one of the sources of waste of energy.

It will be observed that several trials have been made
by different experimenters relative to the hoisting and lifting
power of screws, the latter of large size, acting vertically and
supported and balanced on an arrangement suitable for
ascertaining the actual lifting power in pounds beyond the
equipoise that a man is capable of raising by his own
muscular force, the results have varied considerably according
to the perfection of the mechanism ; but it has been proved
that a man can sustain a weight by this means equal to pqe-
thixd-that of his own body, and as the result seems to depend
on the construction and its most appropriate form, some
hopes may be entertained that, by improvements, this lifting
force may be far exceeded. Though it is not to be expected
that a man can ever entirely lift himself in air by such a
machine, yet the experiments are important and interesting
as bearing on the question of the use of inclined vanes rotating
like a screw, as a means of propulsion only. With all the
tried experiments that have come to our knowledge, we can
safely say that up to the present time no man has yet adapted

OF GREAT BRITAIN.

S.j

himself to a machine that has fulfilled what we have learned
to consider the true law and principle of flight in order to
test the lifting force during a rapid horizontal course. It is
under this condition only that the substratum of air passed
over — on account of the enormous weight of air impinging
on the aeroplane in a brief time — cannot be deflected to
any great extent by the comparatively trifling weight of the
machine, which, under these conditions, finds an unyielding
support. There are very great difficulties in the way of
trying the necessary preliminary experiments, which can
only be curried out satisfactorily in an open car attached to u
railway train at a high speed.

AERONAUTICAL SOCIETY

MEMBERS.

Alexander, A., M.A., C.E., Cyclops Steel and Iron Works, Sheffield ;
of the Council

Anderson, A. Dunlop, 23rd Punjab Pioneers, 21, Lennox Street,
Edinburgh

Arbuthnot, H. Gough, 40, Prince’s Gate, s.w.

Argyll, His Grace the Duke of, F.R.S. ; President of the Council
Armour, James, C.E., Gateshead
Ashbury, James, 66, Grosvenor Square, w.

Ballard, Stephen, C.E., Colwall, Great Malvern
Barker, William, 9, “The Boltons,” Kensington, w.

Baring, Colonel, 36, Wilton Place, s.w.

BaR nett, E. W., 25, Lancaster Gate, w.

Barrett, Frederick, Langley House, Grove Lane, Camberwell, 8.R.
Baxter, Richard, F.R.G.S., 19, Leinster Gardens, w.

Beadon, Captain R. X., Creechbarrow, Taunton

Beauclerk, William Nelthokpe, Foreign Office

Bell, Charles W., Roche Court, near Salisbury

Bennett, T. J., 20, Little Clarendon Street, Oxford

Borthwick, Lord, 35; Hertford Street, May Fair

Bourne, John Fred., C.E., Louth, and Civil Service Club

Bourne, Edwin, 3, Stafford Street, Wellington, Salop

Bovill, William Edward, 22, James’s Street, Buckingham Gate, s.w.

Bowden, A. J., 41, Lamb’s Conduit Street

Bowles, Thomas G., 88, St. James Street, s.w.

Brearey, Fred. W., Maidenstone Hill, Blaekheath ; of the Council,
and Honorary Secrcta'ny

Bright, Sir Charles Tiltston, F.R.A.S., 26, Duke Street, Westminster,
s.w. ; of the Council

Brooke, Charles, M.A., F.R.S., 16, Fitzroy Square; of the Council
Brooks, Maurice, 10, York Terrace, Regent's Park

OF GREAT BRITAIN,

Brown, David Stevens, Braywick House, Green Lanes, Stoke
Newington

Browning, John, F.R. A.S., 111, Minories, and 63, Strand ; of the Council
Brunton, N. W., 116, Belsize Park Gardens, N.w.

Burnaby, Captain, Royal Horse Guards

Burrell, Edward, The Hermitage, 7, Melina Place, St. John’s Wood
Burton, Rev. Roger Taylor, M.A., Lexden Villa, near Colchester
Butler, William Fred., C.E., 5, Cannon Row, s.w.

Chaplin, James C., 12, Craven Hill, Hyde Park
Chatto, Andrew, 74, Piccadilly
Childs, Thomas, Beaufort House, Ham

Clare, Walter F., Engineer, 2, Agnes Cottages, Elm Grove,
Hammersmith

Clarke, Charles, 1, Coburg Place, Bayswater Road

Grestadoro, Dr., Free Libraries, Manchester

Crosland, J. M., Holly Lodge, Thistle Grove, South Kensiagton

Davies, Charles, 47, Pall Mall

Dawson, G. J. Crosbie, C.E., Rowley Park, Stafford

Decruz, E., Seetarampore Colleriesy Raneegunge, Lower Bengal, India

Delane, John T., 16, Sergeant’s Inn, Fleet Street

De Villeneuve, Dr., Rue Lafayette 95, Paris

Diamond, Hugh W., M.D., F.S.A., Twickenham House ; of the Council
Duffkrin, Earl of, 8, Grosvenor Square ; Vice-President of the Council
Englefield, Charles, 5, Springfield Road, Kingston-on-Thames
Fairbairn, Sir William, Bart., LL.D., F.R.S., Manchester
Ganthony, Richard, Eton Lodge, Richmond
Garstang, James, Bank-top Foundry, Blackburn
Glaisher, James, F.R.S., F.R.A.S., & c., Blackheath ; of the Council
Greenfield, Captain J. Tyndall, 17th Brigade R. A.

Greetham, Thomas, 26, Bedford Row, w.c.

Grosvenor, Lord Richard, M.P., F.R.G.S., 76, Brook Street, w. ;
Vice-President of the Council

Hall, George Samuel, Saville House, near Billingshurst, near Horsham.
Sussex

Hammant, W., 32, Bouverie Street, Fleet Street
Harrison, A. Stewart, 133, Upper Thames Street

AERONAUTICAL SOCIETY

Harte, Richard, 2, Devonshire Terrace, Notting Hill Hate
Hay, Rear Admiral Lord .John, 149, Piccadilly ; of the Council
Hodges, F., Leicester
Holland, Robert, Stanmore, Middlesex

Howell, Charles Augustus, C.E., F.S.A., Northend Grove, Northern!,
Fulham

Ingall, W. T. F. M., Greenhithe, Kent

Jay, R. C., 54, Alexandra Road, Cambridge Gardens, Kilburn, w.
Jennings, William, F.R.G.S., 13, Victoria Street
Krueger, W. G., Downeville, Sierra County, California
Latham, Baldwin, C.E., 7, Westminster Chambers
Le Feuvre, Wm. H., C.E., F.R.G.S., St. Antholin’s Chambers,

26, Budge Row, Cannon Street, E.C. ; of the Council
Lilienthall, Otto, Albrecht St. 13, Berlin
Lindsay, Lord, 47, Brook Street, w.

Londonderry, the Marquis of, Holdernesse House, Park Lane
Longridge, James A., C.E., 3, Westminster Chambers
Ludeke, J. Ernest F., 15, Wilmot Place, n.w.

Macdonald, Colonel, Assistant Adjutant-General, Dover
Marriott, Frederick, San Francisco, California
Matthews, Edwin, 26, Bedford Row, w.c.

Maxwell, Captain R. J., Army and Navy Club, s.w.

Michaels, J. Porter, Christinen Gasse, No. 4, Kolowratring, Vienna

Moilliet, J. Keir, Bishop’s Frome, Bromyard

Morrieson, Colonel R., Oriental Club

Moy, Thomas, 37, Farringdon Street

Mulliner, F., 59, Great Charlotte Street, Liverpool

Nees, Christopher, Telegraph Director, Elsinore, Denmark

Newman, Frederick, -C.E., 51, Belsize Road

Ofenheim, Victor R. Von, Schwarzenberg Strasse 18, Vienna

Ohben, Magnus, A.I.C.E., F.C.S., Lower Sydenham ; of ike Council

Osler, Abraham Follett, F.R.S., Birmingham

Penaud, Alphonse, Archiviste de la Socidte Navigation Aerienne,
14, Rue Castellane, Paris

Perigal, Henry, Jun., 9, North Crescent, Bedford Square
Phillips, W. H., Cemetery Road, Nunhead

of great Britain.

Procter, J., Old Castle Buildings, Preeson’s Row, Liverpool
Reeves, Thomas, 16, Burton Street, Pimlico
Risley, J. B., C.E., Brondeg, Ferryside, South Wales
Roberts, Major H. C., 48, Hereford Road, Bayswater
Rumble, Fred. Ireland, 9, Bridge Terrace, Harrow Road
Satrustequi, Don Joaquin Marcos de, Consul General de Espafia,
21 , Billiter Street

Senegal, P., 95, High Street, Kensington
Shill, Richard E., 37, Farringdon Street

Siemens, C. W., C.E., F.R.S., 3, Great George Street, Westminster
Spencer, Charles, Dungannon Cottage, Knightsbridge Barracks
Stringfellow, John, Chard, Somerset

Sutherland, His Grace the Duke of ; Vice-President of the Council
Szyrma, The Rev. W. S. Sach, St Augustine’s College, Canterbury
Thorman, A. J., 281, New Cross Road, S.E.

Tolme, J. H., C.E., 9, Victoria Street, Westminster
Tracy, The Honourable Henry Hanburt, Gregynog Newtown, Mont¬
gomeryshire

Vogt, H. C. de, 23, Gloucester Place, Hyde Park
Walker, Charles Clement, Lilleshall Old Hall, Salop
Walker, Thomas, 24, Oxford Street, Birmingham
Wartegg, E. A. von Flesse, Engineer, 15, Burton Crescent
Wenham, F. H., C.E, V.P.R.M.S., Padnall Hall, Chadwell, Essex;
of the Council

Williams, G., 3, Wellesley Villas, Croydon

Wright, Henry, Stafford House, St James’; of the Council

York, Pierce Wynne, Dyffryn Aled, Abergele

AZROJj^trttCAIi &OCIKTY

PRESENTED BY THE COMMISSIONERS

THE FOLLOWING

SPECIFICATIONS OF PATENTS.

No.

245

277®

Date
1873.
Jan. 31.

Subject.
Aerial Tramways

Patentee.

j Henry Jno. Puckle
i Richard Fenelly.

Aug. 21. Improvements in the Construction'
of Balloons and other Aerial
Bodies, and in the Means of
Navigating them so as to control
the direction in which they
shall move or travel .

•Margaret Martin.

3309 Oct 11. Improved Method of, and Appli- \
ances for, determining the course f
or direction of bodies in air and ( ^eurJ-

water . '

4255

4279

Dec. 27.
Doc. 30.

Aeronautical Apparatus . Jeafa Chas. Gaveau

Improvements in Apparatus for'
raising, forcing, and exhausting
Water, Air, or other Fluid ;
also for lifting, directing, and

J ohn Collis Browne.

guiding Balloons and Flying
Machines . -

OF GREAT BRITAIN.

BOOKS, PAMPHLETS, &c„ RECEIVED.

An Account of the First Aerial Voyage in England, in a Series of Letters
to his Guardian, Chevalier Gherardo Compagni, by Vincent
Lunabdi, Esq., Secretary to the Neapolitan Ambassador,
with his Autograph ; published in 1784. — Presented by Mr. H. S.
Richardson.

Autograph Letter of — Cocking, who lost his life by descending in a
Parachute. — Presented by Mr. H. S. Richardson.

Smithsonian Reports, 3 vols. — Presented by the Smithsonian Institu¬
tion, Washington.

Screw Blades. — Presented by H. C. Linfield, Esq.

India Trigonometrical Survey. — Presented by the India Office.

L' Aeronauts, Monthly Reports of the Aeronautical Society of France. —
Presented by Mons. le Docteur De Villeneuve.

II Problema delV Aeronautica Letter a del Prof. Pasquale Cordemonb
al Signor Alessandro Ferretti. — Presented by the Author.

Problema deU' Aeronautica, Soluzione del Dott. PaSQUALE Cordenons,
Professore di Matematica Nel Ragio Liceo di Rovigo. — Presented
by the Author.

Supposizioni di Nautica Eterea per Volante Alessandro. — Presented
by the Author.

Daily Bulletin of the Signal Service, U.S.A., with the Synopses, Probabili¬
ties, and Facts, Sept., 1872. — Presented by the War Office, U.S.A

INDEX - ‘WINGS FOR MAN.'

Par. Chapter I.

1 Form of wheel . .

2 Displacement area of planes .

3 Rotation ronnd the axis .

4 Curved path, weight floated .

5 Wheel on a rail, floating pressure .

6 Curved path shortened .

7 Wheel suspended, action of the planes

8 Coefficients of resistance .

9 Pressure displacing both wheel and air .

10 Area of resistance to rotation

11 Coefficients of resistance

12 Traction force in air . .

13 Traction force in curved path

Chapter II.

14 Sine*, cosine*, radius*

15 Mean velocities .

16 Plane falling vertically

17 Air columns of resistanoe .

18 Pressure due to velocity of rotation

19 Mean pressure on inclined surface

20 Inertia value of columns of air resistance

21 Inertia value in natural fall .

22 Action of planes on rising side of wheel

Chapter III.

23 Unit force, shift to new air .

24 Velocities in relation to area

25 Extended area taking the place of time ...

26 Centre of gravity, planes revolving round it

27 Horizontal motion of wheel .

28 Zero in Fig. 1

29 Horizontal extension of path .

30 Maximum force. Fig. 1 .

31 .. .. Fig. 2

Chapter IV.

32 Mean -ratio force

S3 Sines, tangents, &c .

34 Traction power per foot of plane

35 Inertia value of traction power

36 Elasticity of air

37 Ratio of propelling area

38 Mean velocity, plane edge resistance

39 Edge resistance, motive power

Page.

• • »*

. 29

.. 30

.. 31

.. 33
34
. 36

37
*•

.. 38

39
»*

»»

42
»»

... >»
... 44

Par. Chapter V. Page.

40 The floating and propelling pressures . 44

41 Diameter of wheel . 45

42 Rising power of wheel . .

43 Weight less than pressure . .

44 Planes spread out upon the curve .

45 Rise from sloping ground . 46

46 Pocus of the plane’s inclination shifted .

47 Wheel going against the wind . .

48 Inclined plane launched against the wind . 47

Chapter VI.

49 Means to regulate the inclination of the planes . 48

50 Cords . 49

61 Motive power on platform . „

52 Access to the interior . 50

53 Rudder .

54 Wheel must continue rotating . .

55 Planes oscillating .... 51

56 The diameter of the wheel . ,,

Chapter VII.

57 Summing-up the forces . 52

58 Resistance on plane edges . .

59 Whole weight floated . 53

60 Journal friction . 54

61 Total piston pressure . .

62 Area of piston .

63 Horse-power of engine . 55

Chapter VIII.

64 Planes to oscillate merely . 55

65 The curved path of rotation . 56

66 Planes horizontal, lifting power ... ., .

67 Horizontal mean power or curve . .

68 The arc of oscillation .

69 Mean pressure for traction . 67

70 Resultant path of the angle of inclination .

71 Propelling power per foot of plane .

72 „ „ for wheel . 68

73 Plane edge resistance . .

74 Resistance on rising side of wheel . .

75 Velocity increased .

76 The inclination of the planes must be variable . .

Chapter IX.

77 Oscillating planes, hollow form . 59

78 Planes horizontal, for quiet floating . 69

Chapter X.

Par.

80
81
82

84
86

97
»»

99
100
101
102

103

104
106
106

Inertia resistance .

Standard value .

Wing shifting horizontally .

Quicker shifts .

Velocity of stroke .

Hinged wings .

Wings in ranged series .

Chaptee XL

Wheel-plane gearing .

Eccentric motion .

Weight of gearing .

Chaptee XII.

Falling planes .

Shifted horizontally .

Standard rate .

Excess rate .

„ half area .

Standard burden, half area .

Lateral extension of plane ... .

»» »• »» ••• •••

Chapter XIII.

Flight of birds .

Air abutment .

Commencing flight .

Wing impelling force .

Up-stroke of wing .

Times of up and down strokes .

Albatross .

Angle of wing plane .

Quicker wing-strokes .

Wing leverage .

Elasticity of air reacting on wing in motion

Page.

... 66
... 68
... 70

75
»»

»•

THOMAS

MOY’S AERIAL STEAMER

»°oq i /c/\

flmlji Annual JUport

OF THE

aeronautical society

GREAT BRITAIN.

FOR THE 'VE-A.E, 1874.

PRINTED BT

HENRY S. RICHARDSON,

GREENWICH.

Reprislaved and printed photolitlio offset for
Peter .Mr kray Hill (Hulilisliers) Ltd.

73 Sloan k Avexie
London S.W.3
1 056

Jifl permission of the Royal Aeronaut irnl Society

MADE AND PRINTED IN GREAT BRITAIN 1IY
IK R. HILLMAN iV SONS LTD., FROM K

AERONAUTICAL SOCIETY OP GREAT BRITAIN.

- -

Pregfontt,

HIS GRACE THE DUKE OF ARGYLL. K.T.

U{ce=Ptegftientg,

HIS GRACE THE DUKE OF SUTHERLAND.
RIGHT HON. THE EARL OF DUFFERIN.

LORD RICHARD GROSYENOR, M.P.

Pfanorarg Sccrctarg, •

FRED. W. BREAREY, Esq.

Pfonorarg Soltritorg,

Messrs. MATTHEWS & GREETHAM, 26, Bedford Row.

Council,

A. ALEXANDER, Esq., C.E., M.A., Sheffield.

FRED. W. BREAREY, Esq., Maidenstone Hill, Blackheath.

Sib CHAS. T. BRIGHT, F.R.A.S., 26, Duke St., Westminster.
CHARLES BROOKE, Esq., M.A., F.R.S., 16, Fitzroy Square.
JOHN BROWNING, Esq., E.R.A.S., F.R.M.S., 111, Minoriee, and
63, Strand.

Major BURNABY, Royal Horse Guards.

HUGH W. DIAMOND, Esq., M.D., F.S.A., Twickenham.

JAMES GLAISHER, Esq., F.R.S., F.R.A.S., Blackheath.
Rear-Admiral Lord JOHN HAY, C.B., 149, Piccadilly.

W. H. LE FEUVRE, Esq., C.E., F.R.G.S., 28, Brunswick Gardens.
MAGNUS OHREN, Esq., A.I.C.E., F.C.S., Lower Sydenham.
Lord LINDSAY, F.R.A.S., 47, Brook Street
F. H. WENHAM, Esq., C.E., Y.P.R.M.S., Padnall Hall, Chadwell,
Essex.

HENRY WRIGHT, Esq., Stafford House, St. James’.

WITH POWER TO ADD TO THEIR BOMBER.

Member’s Subscription, £1. Is. per annum, dating from the day of Election
Ladies may become Associates upon the same terms,

Ifrnfjr gdtttual gtporf

OK THE

AERONAUTICAL SOCIETY OF GREAT BRITAIN,

FOR THE YEAR 1874.

Containing an Account of the Proceedings, and a Selection from the
Papers and Communications received by the Society during the
year, with concluding Remarks upon the present state of the
Science.

The Annual General Meeting of Members of this Society
was held in the Rooms of the Society of Arts, on Thursday
Evening, the 15th of May, 1874. Mr. Browning, F.R.A.S.,
presided.

Mr. Feed. W. Bee are y, the Secretary, read the minutes of
the previous meeting, which were duly confirmed.

Mr. Beeaeey stated that since last Meeting a gentleman
in France had constructed a model which would fly by the
wing alone ; it weighed about three ounces, measured 32 inches
from tip to tip, and would fly 50 feet. They had also been
constructing in New York, an apparatus with superposed aero¬
planes 10 feet in diameter, nlade of sheet-iron, worked by an
engine of 15 horse power, and weighing three tons. It
was 58 feet high and carried a car. It had been exhibited
at so much a head but had not yet been tried. Perhaps he
ought to caution the Members because he believed it was
intended to bring it over and exhibit it here. It was of no
use from the point of view taken by that Society, because it

AERONAUTICAL SOCIETY

would be impossible to raise a machine of that weight with
15 -horse power.

The Chairman : Mr. Moy will first address the Meeting on
the experiments conducted at Messrs. Penn’s, Greenwich, for
the furtherance of the work of the Society.

Mr. Moy said they would remember that some time ago
some very interesting and valuable experiments were made at
Messrs. Penn’s factory, at Greenwich. The results of those
experiments went far beyond his expectations in favour of aerial
navigation, and gave upward pressures at small angles which
were not expected from any existing theory. From the data
furnished by these experiments, Mr. Moy had constructed a
diagram of curves for pressures at different angles, and at
speeds varying from 10 to 10 miles an hour. If they looked
at the diagram they would see that from a perpendicular
position down to 45 degrees there was not much to be gathered.
At 45 degrees the upward pressures and forward resistances
were equal ; but when they came to fine angles, they would
observe that the curves indicating upward pressure showed a
remarkable fulness while the curves of forward resistances were
very small.

As an instance he would take from the tables the speed
to be 40 miles an hour : at ten degrees the upwa rd pressure
was 2 ’841bs. per square foot, while the resistance was only
Q’41b. per square foot. With regard to onward and upward
motion they would find that these curves indicated a
lifting power which it was never before expected to get. These
curves derived from actual experiment explained to his mind
most thoroughly, -how it was that large birds such as rooks and
pigeons were able to -fly with the wings in a rigid state over
considerable distances without any apparent exertion, and
they confirmed and explained what they were continually
observing in nature.

OF GBEAT BEIT AIN.

Mr. Mot had not yet attempted to construct a formula
from these experiments, and perhaps some clever geometrician
or mathematician would do so at a future time, and thus de¬
monstrate the true law of air resistance. He trusted that
members would turn their attention to the results obtained
from these experiments, for he looked upon them as very
essential to those who were making experiments in flying.
He had no doubt that less horse power would be required
than had frequently been anticipated.

Mr. Mot next stated that he understood that some time ago
Mr. Goxwell had promised to assist in trying experiments with
a balloon with a vertical screw, in order that the balloon might
be raised or lowered at pleasure, by manual or other power.
Mr. Coxwell’s ill-health unfortunately prevented him carrying
out these experiments.

Mr. Beeabet : That was 18 months ago.

Mr. Mot said that Mr. Glaisher had lately had a conversa¬
tion with him as to carrying out these experiments, and which
Mr. Brearey was also anxious to see carrried out. He (Mr. Moy)
proposed a plan composed of two hoops, the inner hoop being sus¬
pended to the balloon in the usual position, and the second hoop
being large enough to surround the first hoop and revolve on rollers
with a driving wheel and cranked axle, this axle to be actuated
by two of the occupants of the car by means of treadles. He
calculated 40 revolutions per minute of the axle would be a
reasonable speed. Outside the outer hoop a number of aero¬
planes would be fixed ; the angles of which would be capable
of alteration for experiment. By these means Mr. Moy thought
that a lifting power of from 30 to 40 pounds could be ensured,
and ascent and descent to that extent would be obtained with¬
out throwing out ballast or letting out gas. It would form an
excellent summer afternoon’s excursion to be able to float with
the wind, and to ascend and desoend at pleasure. He under-

AERONAUTICAL SOCIETY

stood the Society were going to purchase a balloon which
would afford the means of furthering the object in view.
‘A third subject which he wished to speak upon, was their own
aerial machine. They had not got on so fast as they had hoped.
Various difficulties had arisen which had to be mastered
one by one as they cropped up. As their machine was only a
forking model the aeroplanes required to be made of some
light material. Some time ago he was trying to get thin steel
rolled and corrugated but he was unable to get anything suitable.
He next tided a fine kind of brown holland for their wing sails,
but they found this would not take the curves kindly but got into
wrinkles. He was now making use of thin pine laths nicely
planed and carefully fitted so as to form a sectional screw sur¬
face, and he thought they would answer very well, and would
form the nearest approach to a perfect screw that could be
obtained. He hoped that in a snort time they would be able
to try further experiments.

The Chairman said that before he entered upon any remarks
he would ask visitors who were present to consider themselves as
members of the Society for the time being, and would invite them
to take part in the discussion. The Society would be pleased to
hear them. From the time when he was twelve years of age he
had watched the flight of birds, and he had noticed that they
never set their wings at any large angle except for the
purpose of stopping themselves. The observations that had
been made and the tables would be very valuable to the Society,
and he thought they ought to have the tables printed. It had
recently come to his knowledge that these experiments at Messrs.
Penns’ would be very useful to engineers. Doubts had been
cast on those adduced by Mr. Nunn, but when he heard of
these experiments of Mr. Wenham. at Messrs. Penns’, he got
the tables examined and he found they gave the same results
as he had arrived at. Opposition was of course then at

OF GREAT BRIT AIK.

an end. As regards the suggestion that had been made, and
which was now being carried out, that a balloon should
be fitted with revolving apparatus and a power which could
be exerted by two men, should be tried ; their friend Mr. Brooke
had given some valuable advice. It was not so well known
as it should be that Mr. Charles Brooke had done a great deal
of work in his lifetime for which the scientific public were
much indebted to him ; therefore the earliest opportunities
should be taken to give publicity to his valuable suggestions.
The first suggestion was that the balloon should have weights
placed in the car, that would exactly keep it on the ground.
These weights should more than counterbalance the balloon,
but as little as possible. Then he (the Chairman) suggested
that there would be a difficulty in finding out what the effect
of revolving fans would be, because the balloon would be in the
position of a captive balloon, and would have to contend with
the action of the wind upon the fans, which would tend
to raise the balloon. The first thing required was that
they should ask the Directors of the Crystal Palace to allow the
experiment to be tried there, but that might be answered by
the objection entertained to keeping so large an amount of gas
within the building. Mr. Wenham bore him out in saying that
they would have great difficulty in getting satisfactory results
from a balloon used in that way, because when a balloon travelled
in the air it was affected by the wind, while as long as it
remained on the ground it might be considered as a captive
balloon, and therefore the pianos would depend upon the power
of the wind passing through them. With regard to Mr. Brooke’s
suggestion that gentleman thought it desirable to dispense with
the balloon altogether. The balloon was a resisting force. Let
them suppose instead of having the balloon attached to this rota¬
ting fan, which was being worked by two men, they had a rope
attached to the centre of a fan and carried it over a pulley ; it was

aeronautical society

quite evident that the experiment could be made quite as well by
these means as by means of a balloon. They would get rid of the
disturbing force of wind on a large surface, and no one would
have any objection to allow the experiment to be tried in a closed
building. The effects might be tested by self-registering
apparatus, of which, with the permission of the Council, he
purposed making a present to the Society. He would like
further to remark that it seemed to be the idea of the Council
that this was simply an experiment to see what effect could be
obtained by rotating planes in this manner, and was not made
with any idea of balloon propulsion except in the way indicated.
He would now suggest that a vote of thanks should be given to
Mr. Moy for the paper and diagrams ; and he should propose
that the tables which Mr. Moy had promised should be printed
in the Society’s proceedings.

Mr. Rkearkt said he had a short communication to
read from Mr. Artingstall, of Manchester, as follows —

'‘You will no doubt remember that I have frequently
intimated in writing to you that I did not believe that true
flight is accomplished by waftage, or windlike action, as a ship
is driven, a windmill turned, a boy’s kite supported, or as an
aerial screw acts ; but that the pulsations or waves of air play
an important part in flight ; yet they cannot be easily utilized
artificially as it depends upon the dexterity of action in the wing,
if I may so speak, to ‘ catch them.’ This, the feel of a bird’s
or bat’ 8 wings easily and naturally accomplishes. The follow¬
ing may perhaps bear on the subject : —

“I once mentioned to you in a letter a curious effect I
produced by striking the air with the edge of the wing : — The
following is an improvement on that experiment.

Of eBEAT BRITAIN.

Fig. 1.

Fig. 8.

“Let A A, Fig. 1, be the thick edge of an artificial wing ;
BB the thin edge ; H the handle. The stem of the wing is
attached to the centre PP that turns to the iron fork F. To
operate with this instrument, take hold of the handle H, and
use the wing as though it was an axe or chopper, and by a slow
stroke, endeavour to cut the air with the thin edge of the wing.
The elastic materials of which it is made, will allow the plane
of the wing to turn either one way or the other, and the
oblique action will drive it as far as it can go sideways (see
Fig. 2), on the principle of oblique surfaces acting in the air.
This is easily conceived ; but the following is not so, if you

AERONAUTICAL SOCIETY

hold the wing steadily by the handle H (Fig. 1), and the stem
horizontal, and in a line with the handle, allowing the plane
of the wing to hang perpendicularly as in Fig. 1. All being
now prepared, endeavour to cut the air as before by a quick
stroke downwards. Ip you hit upon the right position, the
wing no longer appears to obey the ordinary laws of resistance
of air but gives a powerful pulsation, and instead of being driven
according to its obliquity positively goes in the opposite direction.
This experiment requires a little practice to work it well, and to
catch the exact point of pulsation.

“I hope some Member of the Aeronautical Society will
solve the problem ; perhaps it is very easy after all, but / can¬
not see the solution at present.

“ I map attach too much importance to the pulsatory action
of air in flight, but that some such action takes place I have
proved by experiment, to my own satisfaction.

“ The resistance of air being as the * squares of the velocities’
is a mere school or college absurdity. The resistance depends
upon the form of surface, the mode or condition of impact, &c.
The effect of military projectiles, and the theory of their motions
is much nearer the truth when applied to the impact of air, or
what is the same thing, impact of sufaces against air.”

The writer said he would have sent a model but it
was only in a rough and unfinished state.

The Chairman remarked that it was a great pity the
gentleman had any scruples about sending his model, because
even engineers rarely made their trials with materials of
finished workmanship. The model would have enabled them
to try an experiment and might have brought forth remarks on
the subject. As it was he would ask them to pass a vote of
thanks to the author of the paper.

Mr. Brooke said he would only offer one remark as to the

OF GBEAT BEIT AIN.

resistance being in proportion to the square of the velocity.
It was supposed that the particles resisting the motion as soon
as they came in contact were annihilated, and only fresh
particles came in contact with the moving body. This was at
variance with what really must occur. The particles were
compressed and had all to get out of the way sideways. The
simple resistance and velocity were not sufficiently taken into
account in the experiments at Penn’s. It was supposed that
whether the plane was placed so (referring to diagram) at 45
degrees, or so (at a less angle), the resistance would be the
same in both cases, whereas it was found to be practically
different. Suppose one was placed at 45 degrees to a current
of air, it was clear that the air must pass along the surface of
the plane. The resistance of a plane placed at the same angle,
but in another position, would be different, whereas, according
to mere mathematical law, they ought to be exactly alike.

A Membee : How large was your current of air, and what
size was the disc ?

Mr. Wenham : I think the largest was two square feet.

The Chaieman : Six inches by two feet.

The Membee : What size was the current of air ?

Mr. Bbooke : It was passed through a shaft 18 inches
wide. The object was about two feet in front of the current
of air, but this did not make much difference. Of course the
object must not be too far from the current of air.

The Chaieman said it would perhaps be agreeable to the
Meeting that the results of the experiments should be read.

The results were read accordingly.

Mr. Wenham said that the law of the square of the
velocity applied to water, and that a very different law applied
to an elastic medium like air, where the resistance took a very
different form to what it would in water. The law in regard
to water had been approximately ascertained, and he thought.

AMEOWAtmCAt mettTY

with regard to the air, the law, wheti enquired into, would be
equally recognizable.

Mr. D. 8. Brown read the following paper : —

THE AERO-BI-PLANE,

FIRST STEPS TO FLIGHT.

In a former paper on the aeroplane, I described how its
stability could be increased by employing two planes for support,
one placed before the other. By experiments which I have
since tnade, I find this improvement can be carried still further
by constructing the anterior edges, or frames, of the planes
rigid, and the other parts yielding or elastic. The modification
admits too of the car or load being placed between the planes,
and without any other force than gravity the bi-plane when
elevated will proceed for a considerable distance in an oblique
direction until it reaches the ground. Indeed, in this simple
form, it may be aptly termed a progressive parachute. But
with the aid of manual or other power the distance to which it
could be propelled horizontally would be more or less increased,
or the machine maintained permanently in the air. Nor are
these the only advantages which it possesses. All shaking is
either prevented or utilized. For if it be of a pitching kind the
planes act as fish-tail propellers ; or, if of a rolling kind, as
wing propellers.

The apparatus is also able to descend very lightly, which
is accomplished by bringing it, or the planes by means of the
rudder, suddenly into a large angle with the horizon, which at
once stops all motion precisely as done by a bird when it alights.

Fig. 2.

Fig. 1.

Vot.2. . BOOK 9.

OF GREAT BRITAIN.

Notwithstanding the elasticity of the planes they will he kept
in their proper position by the air when moving through it, and
all strain upon them prevented, affording at the same time
ample support. As regards propulsion, a wing motion, which
must necessarily be a slow one, can be given to either one or
both of the planes, or a small pair of propelling wings may be
attached to the car.

A man in a recumbent position offers very little resistance
to the air and yet can exert great force with his feet in working
a bellows engine, or they may be moved by a steam engine in
a very simple way if the shafts or shoulders of the wings
terminate in forks or prongs. A bar fixed to the top of a
vertical piston rod and passing crosswise through the forks
would then elevate and depress them at every stroke. The
revolution of a crank in the forks turned by a spring would
have the same effect.

Fig. 1 represents the improved bi-plane, a being the car,
bb the planes which are divided at their centres in order to
allow the rods or poles cc, which connect them, to pass to the
forward edge of the anterior plane, and also to extend beyond
the limitB of the posterior one to support in a good position the
rudder d consisting of two planes, one set vertically and the
other horizontally.

Fig. 2 shows a modification of the apparatus, the anterior
frames of both planes being curved to diminish the resistance
of the air, and the posterior parts may consist of cord. Unlike
a ship or wheel carriage, the bi-plane can only be supported by
the air when it is in motion, as illustrated by a slate thrown
upon smooth water, which is then sustained when moving
horizontally without any inclination of its surface. It is there¬
fore necessary that the apparatus should start with an initial
motion, which may be given by an india-rubber rope fastened
at one end to a post, and at the other, by means of a ring, tQ

AERONAUTICAL SOCIETY

a vertical bolt inserted in the under part of the bi-plane. On
stretching the india-rubber by drawing the machine backwards,
it will afterwards spring forwards with any required velocity, at
the same time releasing itself from the rope as the ring falls
from the bolt when the rope slackens. With respect to the
proportion of weight to surface, that will depend upon the
velocity.

I may mention, however, that in the experiments made by
Sir George Cayley, a square foot was found to support more
than 21bs., and the Australian crane, a very large bird, weighing
upwards of 20lbs., and one of the best flyers, is loaded to the
extent of about 2£lbs. to the foot ; whilst the crow only carries
lib. to the same surface, and smaller birds and insects much
less weight still in proportion.

As the advantages to be derived from the perfection of
aerial navigation are not sufficiently appreciated or understood,
I will, in conclusion, briefly state them. It will combine the
independence of a private carriage with the speed of an express
train, and a person will often be able to arrive at the end of his
journey by the time it now takes to start from the nearest
railway station. Aided however by favourable aerial currents
the voyage would sometimes be made in an incredibly short
time, as now done by birds of passage. It would also be in a
straight line and free from all obstruction. The motion would
be of the most agreeable and least fatiguing kind, resembling
skating, and in warm weather the aeronaut would be able to
choose what temperature to travel in, which would depend upon
the elevation, whilst the expansive and ever changing view
would be unrivalled.

It is very desirable that the attention of country gentlemen
should be attracted more to the subject, because not only have
they the means and leisure, but, what is of the greatest impor¬
tance, ample facilities in their parks for trying the experiments

OF GREAT BRITAIN.

on a large scale, by which alone mechanical flight can be ren¬
dered a reality. I have shown how stability can be combined
with progressive motion and guidance ; how the planeB can be
constructed so that the air will remove the strain from them ;
and how a start and descent can be made with safety. I have
also devoted much attention to motors and find that abundant
resources exist for making them light should extraordinary
lightness prove to be essential.

In the course of general remarks, with which the reading,
illustrations, and experiments were interspersed, he said that
before he began his experiments he thought that power was the
great desideratum, but he soon found that the question of stability
was, if anything, of still more importance not only to ensure
safety but also for economizing the power itself. He had now
constructed a plane which, when thrown into the air at what¬
ever angle, always returned to its normal position. Most of
them would recollect the experiments of Mr. Henson and those
of Mr. Stringfellow, who, at the Exhibition of 1868, contributed
a model of a flying-machine. He had a superabundance of
power, and yet could not release it in the air, because he had
not overcome this difficulty, Mr. Brown thought, however,
that he had done so by using two planes, which gave a Stability
somewhat analagous to what is obtained by supporting a beam
at both ends instead of only at its centre. A weight placed
between the planes constrained them to assume a horizontal
position like a well-ballasted ship, and without the aid of a
rudder. Until this had been accomplished, it could not be
said that they had even laid the foundation-stone of their art,
and it would be for them to say how far he had succeeded.
This (a slight plane of light wood and paper) was the first
form. He would set off with a pitch. That pitch would not
be made in its normal position, but it would return to its

AERONAUTICAL SOCIETY

natural position if there was room for it to do so. The next
improvement was to make the machine elastic, which must
also be done so far as possible in order to perfect its safety.
The machine, he might say, got no support until actually in
motion.

Mr. Brown launched several planes of different dimensions.
All showed perfect stability, and, save one or two, floated in
the air in a horizontal position across the room, a distance of
between twenty and thirty feet, and, apparently, in some
instances could have gone further without falling had not the
walls intervened. One he suddenly pressed downwards in a
perpendicular direction by striking it with a stick when in the
air : this caused it to dart forward with great velocity in a
horizontal course. Mr. Brown considered this an illustration
of true flight, as the planes were only inclined the moment he
struck the connecting-rod. During the flight they recovered
their horizontal position, and offered no resistance to the air.

Mr. Brown added that it was desirable that the attention
of country gentlemen should be attracted to this subject from
time to time, because they had not only means and leisure, but
they had the opportunity of making experiments on a large
scale in their parks.

Mr. Brown next exhibited a shallow boiler made of very
thin metal, containing a little water, for the purpose of inflating
a tiny elastic balloon fixed on the boiler. The object was to
exhibit powers of distension and contraction by the application
and removal of heat in order to imitate wing motion, which
on a large scale must be slow on account of the length and
obliquity of the stroke. This kind of engine required no
valves, and the principle admitted of its being worked as
economically when the pressure of the steam was only 1 poulid
to the inch as when it was 15, which of course was of immense
importance as regards its lightness.

OF GREAT BRITAIN1.

Mr. Mot : What pressure do you work at !

Mr. Brown : This is a mere experiment.

Mr. Mot : What will it bear ?

Mr. Brown : I have here a small aluminium tube 9 inches
long and one in diameter. No doubt it will bear an internal
pressure of lOOlbs. Aluminium is four times as light as
silver, and it can be rolled much thinner than copper, without
cracking like that metal. Unfortunately it cannot be soldered,
but I have succeeded in uniting very thin pieces weighing half
an ounce to the square foot, by sewing them together and
placing a leather or india-rubber washer between the united
parts. This tube appears perfectly made, without a joint, but
how I do not know. It weighs three-quarters of an ounce.

Mr. Brearey : The boiler is now full of water.

Mr. Brown : No, there is only a wineglassful.

Heat was applied, and the bulb slowly expanded, and on
its withdrawal, and the application of a cold sponge, contracted.

Mr. Brown said he was at one time an advocate for steam
flying ; now he thought they ought to try manual power first
for many reasons.

( Model Exhibited.)

Mr. Mot asked the price of the aluminium for constructing
the boiler.

Mr. Brown said about 8s. per oz.

Mr. Wenham said it was about 5s. in bulk.

The Chairman thought it could be got at about 4s. when
taken in quantities. It was quite evident th&t Mr. Brown had
proved that the bi-plane had a tendency to keep its own
position, and this he thought was a matter of some value. If
Mr. Brown gave to it a tendency to an upward direction a long
flight might be obtained. They ought not to pass over
Mr. Brown’s liberality with respect to only patenting his
inventions provisionally. Even experiments begun on false

A EBON AtTTIC AL SOCIETY

hypotheses might lead to valuable results, just as the search
for the philosopher’s stone led alchemists to better discoveries.

In reply to a Member, Mr. Brown said he had not given
up the idea of the use of steam in the air, only he gave the
preference to manual power for a commencement, and if that
failed they could fall back upon steam. On a plane, without
any inclination, he believed man had power to fly, but with
inclination he doubted whether, even with a steam engine, they
could accomplish it.

Mr. Moy considered Mr. Brown’s proposal for preventing
the plane from falling by giving it a partly upward course was
equivalent to inclining it. In fact it was a distinction without
a difference.

Mr. Bbown thought it would be found different in
practice, give greater stability, and offer less resistance. But
the idea did not originate with him.

A Member asked if there had been any experiments m»de
with electricity to give motive power?

The Chairman thought not, and expressed his belief that
engines required for that purpose would be too heavy to use in
the air.

The Member : Has any one tried atmospherical electricity
— getting motive power out of the atmosphere.

The Chairman : No, I have not heard so.

Mr. Brown said an example might be drawn from the
bicycle where manual power was more effective than steam.

A Member : Has there been any experiment with the
view of getting gas out of the atmosphere ?

Mr. Wenham : I am afraid all such schemes must fail.
We never could get aerial machines lighter than one ton
per horse power with either gas or air engines.

Mr. Brown, replying to questions, said it was difficult
to incline one plane and keep it in its position. There
must be two planes if they inclined them.

OF GREAT BRITAIN.

The Chairman said there was another paper, but time
would not permit them to read it.

Mr. S^n^cal remarked that elasticity, so well illustrated
in birds, insects, and fishes, does not seem to be be applied in
apparatuses intended for aerial locomotion.

.The planes of a machine, should be composed of materials
well known for their elastic properties, such as Indiarubber,
steel, &c.

By constructing a machine, structurally and mechanically
on the laws of elasticity, you will reduce it to at least a tenth
part of the original weight ; in the same proportion, the power
for progressive motion will be considerably increased, while the
main or motive power will be reduced to a mere trifle.

He pointed out in Mr. Brown’s model that the planes
should be elastic, not only in the line of motion but also at
right angles to that line. The resultant forces will then be
a forward motion of the whole.

A weighty machine may be very effective at high speed
or in a strong wind; but I think you will require speeial
apparatus for coming down in a calm.

A machine ought to be constructed as light and elastic
consistently with strength to carry a weight (which will be the
equivalent to work done), the whole will be a store for power,
which can be effectively developed as before mentioned.
Elasticity is a force that can give very powerful effects, and
under suitable conditions is capable of being developed almost
indefinitely. An elastic ball will rise according to the force
with which it was thrown on the ground, and yet it is far
from being a proper shape for its production. It is by
elasticity, so well directed, that birds and insects steer them¬
selves with such dexterity and precision.

The Chairman remarked that it was quite true that
under some circumstances elasticity in the apparatus might

AERONAUTICAL SOCIETY

senre as a store of power, but first of all the power must be
communicated before it could be worked. There is considerable
elasticity in the wings of birds, and if a wave of air came in
front of them they availed themselves of it in the most
economical manner.

A vote of thanks was given to the Chairman.

The Meeting then closed.

The following paper by Mr. James Armour, C.E., was taken
as read : —

6# ORB AT BRITAIN.

RESISTANCE TO FALLING PLANES

ON A

PATH OF TRANSLATION.

In a body propelled by planes in motion, the centre of
gravity of the weight of body is assumed to be sustained on a
uniformly level path, to be sustained in the manner of a weight
at rest, without momentum in the direction of support ; where¬
as the propelling planes will move on an undulating air path.

The resistance of the air in the case of bodies moving in it
with moderate velocity, has been experimentally found to vary,
roughly with F* ; consequently, as the density of air is pro¬
portional to the pressure, we have the air which is driven with
velocity 20 ’5*, of about one-fourth the density of air driven
with velocity 41* ; and as the expansive reaction of the pressure
due to density, is weight of resistance to be overcome, we have
the greater or 41 feet velocity carrying the fourfold weight of
resistance through twice the actual space in a given time, so
that the ratio of work done in a -given time is here 8 to 1.

Further, as the resistance to the wing plane in motion" is
for the support of the body, it must be equal to the force of
inertia that the weight of body would develop by free motion
in a given time.

In the case of rotating planes, were they flat and rigid,
the propelling power would have to be performed wholly by
the inclined face of the plane; and as at the flatter angles for
quick motion of translation, the horizontal component for im-

AERONAUTICAL SOCIETY

pulsion, upon winch the maintenance of the motion of translation
depends, would be insufficient, it is evident that some force
distinct from this horizontal component of the flat rigid face is
needed ; and in the following brief observations we hope to
show how this force may be obtained.

In a bird’s wing the front or leading edge is stiff, and the
rear edge is flexible ; flexibility occurring also in the direction of
the length from body joint to tip.

In the case of rotating planes, if the wing plane be flat
and rigid, the expansive reaction of the air that has under¬
gone compression takes place when the plane has passed, and
is therefore so much power let go with, say only half its
capability utilized. Whereas if the plane be possessed of
flexibility at the rear edge, the force of compression that has
taken the time «c Fig. 1, to develop, reacts in the time ab on
the flexible rear membrane of the plane ; and as this reaction
in less time represents greater energy in the act of expansion
than in the act of compression, we have the angle of the curve
at b greater than at c ; and consequently have the impulsive
force / greater than the unit resistance on the face ca.

Fig. l.

The gravity of the weight supported performs the com¬
pression, and in the elastic reaction on the rear edge of the plane.

OF GEEAT BRITAIN.

we have the energy of the compression reacting to impel the
loaded plane along the path of translation.

Assuming that the rotating planes start with the weight
they have to sustain from a state of rest or zero, and without
the support of the ground to run upon, the duty of overcom¬
ing the force of inertia in the whole weight for a given
sustaining velocity of translation would devolve upon the planes
wholly ; and as from a certain distance from the start the
velocity of translation must be slow, and the path of support
for a given time correspondingly short, the velocity of rotation
to give force of stroke sufficient would have to be correspond-
ingly great if the path of flight be horizontal.

At the point however where the sustaining velocity of
translation is reached and continued at uniform rate, we have
the force of inertia of the weight developed for that velocity,
and no longer exacting horizontal impulse from the planes, which
have now only the external resistance to flight to overcome ;
and if we here assume that the velocity of translation is not
less than the velocity of rotation, and may be greater, it
clearly may be assumed likewise that the air abutment is no
longer displaced bodily.

Then further, as the velocity of fall, or stroke, to sustain
a given load, is assumed, and has been experimentally deter¬
mined, to decrease as the velocity of translation increases ;
moreover, as the air abutment is not bodily displaced when the
velocity of translation is not less than the velocity of rotation,
it seems reasonable to assume that the motive power has here
only to impart gliding motion to the planes upon their bed of
compression, the elastic resistance of the bed of compression
forming the sustaining resistance to the weight of- body.

The rotating planes have to descend the height of what
we may term the stroke, but they descend with only the resist-
tance offered to progression in the line of their path.

AERONAUTICAL SOCIETY

As the sustaining air has to be compressed however, the
extent of the compression would be equivalent to fall, unless
the plane be inclined from the path ed Fig. 1.

The weight of body then pressing downward without
energy, forms a balance to the weight of resistance pressing
upwards on the plane face ; and as by reason of the motion of
translation, there is no bodily displacement of the air, the
action of the rotating planes in easy flight upon their path of
support is similar to that of birds’ wings in soaring.

Large birds starting from a perch, or renewing forward
impulse when they have been hovering, are seen to acquire
sustaining velocity very quickly, by letting themselves with
outstretched wings glide downward on an easy gradient;
evidently showing that the acceleration of the forward impulse
on the easy descent, balances by the increasing pressure upon
the wings, the acceleration earthward due to gravity ; the
earthward energy of the weight of body being at zero in the
start from perch or point of hovering.

The air pressure against which the outstretched wings of
a bird have to be sustained, hinged at one end only, gives the
measure of the tension due to pressure and leverage on the
muscular power of the living wing, and the muscular power
has to sustain this tension to the end of the stroke.

In the case of rotating planes spindled at both ends, the
strain of the pressure appears at the spindles ; and if the motive
power be applied at the centre of rotation, we have the pressure
acting with the leverage of the distance from the centre of
rotation to the spindles ; but in the cases of both bird and
artificial plane, we have the angle of inclination in both wing
and plane directing the burdened plane in the way of least
resistance ; and if the expansive reaction of the compressed air,
before spoken of, be at work on the flexible rear edge of the
plane, the motive or engine power required once a sustaining
rate of flight is reached, may be slight.

OF GREAT BBITAltf.

As it has not yet been determined at what rate a wave of
compression is propagated in air, precise value cannot at present
be given to the expansive energy of the wave escaping to react
from a to b, nor to the sustaining force on the faee c a, in relation
to the force resisting the motion of flight on that face. We think
it highly probable, however, that the higher the velocity of the
inclined surface that imposes the pressure, the less the distance
the swell of the wave out from the surface in the time of
passing, consequently the more dense will be the body of the
wave of compression.

The motion cd, Fig. 1, would require to be motion of com¬
pression only, otherwise the expansive reation on ab would lack
air support beneath ; and that the motion cd is of compression
only seems evident from the facility with which birds soar on
an ascending path. Were bodily displacement of the sustaining
air here to occur, the soaring wing would have to follow the
air, to maintain the resistance, as the motion of bodily displace¬
ment implies that as regards the volume of air undergoing
displacement, the force of inertia due to the rate of that motion
has been overcome, and is no longer of avail for support to the
weight possessed of that same motion.

It seems difficult in the case of an artificial wing to
devise a substitute for the light and flexible feather tips that
form the rear edge of a living wing ; and it seems almost vain
to think of artificial means of adjustment of the angle of
inclination such as the sensitive living wing possesses ; thus, it
would be vain to think of continued flight for two dead wings
of a large soaring bird, loaded with weight equal to that of the
bird they had belonged to, and impelled artificially, as the
living bird would be required to keep the angles of inclination
in adjustment with the requirements of the weight that has
to be sustained*

AERONAUTICAL SOCIETY

Fig. 3.

In Fig. 2, let bcnp be the end view of a narrow plane with
its front edge rounded. The expanding fluid curves g, h, i, and,/,
represent the varying pressure of the air in front. The air in
contact with the edge at k, is bearing the full weight of the
imposed pressure due to the velocity ; and as the advancing
edge with its pressure is cushioned on the inert but elastic air
in front, the force of inertia of the air that is continuously to
renew the cushion as the plane advances, is developed
gradually by reason of the elasticity, in such manner that,
beyond a certain point in advance of k (the distance of which
from k is dependent upon the V3 pressure) the air is found at
rest, the force of the pressure having been absorbed by the
inertia of the weight of elastic air between this point and k.

Owing to the elasticity and compressibility of air, the
effort of displacement has not to reach so far out as in the case
of motion through water ; moreover, in high velocities where
little time is allowed for the diffusion of the pressure outwards,
the wave of pressure, though more intense, will reach out a
less distance than in low velocities but the lateral expansion of
the wave will depend greatly upon the length be of the plane,
because, the greater the length be, the longer will be the time
allowed for the expansive force to act outward for relief on the
surrounding air before complete relief be got when closing in
behind.

The compressive force is at its maximum at k, but is at
aero at b because the surface there is rounded into line with

OF GREAT BRITAIN.

the direction of flight. The expanding fluid-curves g, h, i, and
j, however, will have projected the pressure below the line of
plane surface be.

When the velocity is constant, the fluid-wave keeps
uniformly in advance of k, but the curves which we have
employed to represent the varying intensity of the pressure
outward, for example the curve j, we may regard as uniformly
flattening out upon the lines de and bn ; and, in the act of
flattening out, the air is put in motion in the direction
indicated by the arrows ; but this is a motion of compression
mainly, and the faces be and np bear the reaction in such
manner that any slight projection on either of these faces
would have to pass through a denser medium than opposes in
the case of a thin plane.

The greater the velocity of flight, the more sudden will be
the compression of the air in contact with the advancing edge,
and the more compact will be the stratum of displaced air in
contact with the faces be and np ; and, in the case of two or
more planes slightly inclined and moving close together on
parallel paths, the velocity of flight will determine what thick¬
ness of unmoved air will occur between them to form a bed
of support to the weight of plane.

Let the weight to be sustained by 1 sq. ft. of plane be
3’51bs. The inertia force of 2'G961bs. of air pressure impelled

at the rate of 41ft. per second is equal to that of 3-51bs. at

32* 18ft. ; because as the plane is moving — - ■ — 1*27 times

o2-18

as fast in 1 second as the uniform acceleration of gravity, we
have 3\5 1’27 — 2‘6961bs. pressure at the 41ft. rate,

doing as much constant work in the resistance of its inertia as
3 •Mbs. at the 32 • 18ft. rate.

We will assume this to apply to a stationary stroke, on a

AgBOHAUTICAIi SOCIETY

surface of air equal to the single area of the plane in motion ;
and to take the place of this force in a stationary stroke, we
propose to put the inertia force of say 0 '2 3 191b. of air pressure
impelled at. the rate of 1 1 *85ft. per second, equal therefore to
(bO 8541b. and possessed of motion of translation equal to the
velocity of the stationary stroke, viz., 41ft. per second.

In the natural gravitation of the weight, neglecting air
resistance, to acquire 11 ‘85ft. velocity, it would fall 2' 18ft. in
0‘368 sec. ; whereas it would require 1'274 seconds to develop
41ft. velocity, with a fall of 2 6’ lft.

The force of inertia can act only in the direction of the
motion that develops it ; and weight when translated consumes
or absorbs applied force equal to that developed by an equal
velocity in natural gravitatioh ; moreover, the resistance of
inertia is simply equal to the force expended on the given
weight in imparting the given motion to it ; so that, when,
in a given time, that motion becomes uniform, the expended
force is expressed in the motion.

The inertia resistance due to the given uniform pressure
of a single area of air surface in the stationary stroke is
overcome the moment the given uniform velocity of stroke is
reached, for then the previously inert air has received the
compression due to the velocity, and is in motion at the given
rate ; the sensible force upon the plane, however, is the static
uniform pressure due to the density of the compressed air that
forms the cushion of compression ; and, as in displacement of
air occurring in the cushion, the entering air would have
transferred to it the inertia force of the air that is displaced,
in the act of deflexion for displacement, it must necessarily
follow that the force -of inertia developed in the compression of
the cushion determines the value of the support the weight
receives in the stationary stroke ; and any prolongation of the
stationary stroke simply prolongs the duration of the support
by maintaining the compression.

OP GREAT BRITAIN".

The work performed in the formation of the cushion
requires the plane performing it to possess motion of com¬
pression at the given rate. The cushion when formed could
throw out this work again upon external resistance, say back
upon the plane, only by being allowed to expand to its natural
density ; but this motion of expansion is prevented by the
plane maintaining the velocity to which the compression is
due, so that the expansive energy pent up in the cushion
formed is just equal to, so as to be balanced by, the impulsive
energy of the sensible pressure of the plane in motion at the
given rate.

The work performed by the plane in the act of com¬
pression is internal with respect to the cushion of resistance ;
and the motion of compression is at an end when the given
weight of resistance in the cushion is reached, the cushion
being then impelled bodily forward by the plane.

When the plane with its vertical stroke is translated
horizontally, it strikes the air come upon at once with the
given velocity of stroke, and in the time of the compression
expends upon the air the energy that, in free gravity, in
relation to the falling tendency of weight, would be developed
in the time of the fall io which the velocity is due ; and
expends this energy in such manner that the plane would come
to rest for the instant before reaction began, were this single
effort of compression all that it possessed. The velocity of
the plane is assumed to be maintained by the motive power at
uniformly continuous rate, and we may assume, therefore, that
the motion of compression takes part in the uniform velocity
of the plane at the given rate ; but as the force which the
plane expends upon the cushion in the time of the compression
is due to a velocity the value of which, as respects the weight
supported, is represented by the time required in free gravita¬
tion to develop it, we have for the formation of the cushion

aebonauticAl society

the time of the compression ; and for the motion that imparts
compression, the time of its development in the weight in a
free fall ; and as the cushion is on the surface, so to speak, of
the body of air resistance, and receives in the time of the
motion of compression the energy that takes the longer time
required by weight freely gravitating to develop, it seems
evident that, by motion of translation, to shift the plane on to
fresh and unmoved air in the time of the compression, would
give on the path of translation inertia support to the plane in
a given time, say one second, equal to the number of times
the time of compression was contained in one second.

The effort in compression determines the inertia value of
the pressure on the plane at any point or moment of time in
the path of the uniform motion ; but, in the stationary stroke,
we can estimate the value of the continued effort in the plane
in motion only by the work done in a given time and fall.

The force of inertia developed in the cushion for a
stationary stroke concerns the force of inertia that the
supported weight of body would develop in the time for which
the velocity is rated ; so that, for one second, as the force of
inertia due to 3'51bs. weight at 32’lBft. velocity would be
3‘51bs.. we have the force of inertia due to 2-6961bs. pressure
at 41ft. velocity just balancing that of the weight.

To support the translated weight we have to give to the planes
in the given time 1‘0, the force that the weight itself would
develop in that time by a free fall ; but so that each unit of
length in the area of the air path travelled by the plane in
one second of time shall contribute resistance of inertia equal to
the force which the' weight would develop in the time occupied
in travelling that unit of length if falling freely ; in which
case the weight of body as represented by its developed unit
inertia would act in the manner of a load distributed over the
path of resistance.

OF GBEAT BRITAIN.

In the following terms we seek to show the relative
equality of the different pressures at the different rates of
translation, the effect of resistance to flight being here
neglected : —

Actual energy in the given falling weight ; or the work
performed by gravity, and accumulated in the weight when
the falling motion reaches the given rates of velocity in the
respective times.

Time ratio. ft. vel. ft. falL lbs. Units’ work.

1 j 0-637 sec. - 20-5 = 6-56 x 3-5 = 22-96

2 ( 1-27 „ - 410 = 26-1 x 3-5 r: 9135

1 to 4 1 to 4

1 ( 0-368 „ - 11-85 = 2-18 x 3*5 = 7-63

3-46 l 1-27 „ - 41 0 = 26-1 x 3 5 = 9135

1 to 12 1 to 12

1-0 „ - 3218 = 16-0 x 3-5 = 56-31

and 56-31 : 91 35 : : 16 0 : 26-1.

Air pressure on the sustaining planes ; the energy
appearing in the resistance to the planes in motion, and not
to the weight to be sustained.

VeL Uniform Uniform Inertia

ratio. ft.veL pressure. inertia. ratio.

1 t 20-5 = 0 67971b. = 0-4331b. \ _ 2J

2 ( 41-0 = 2-696 =3-5

1 to 4 1 to 8

l*to 2* l3 to 2*

1 | 11-85 = 0231b. = 0 08541b. \
3A6 ( 41 0 = 2-696 =3-5 )'

1 to 12 1 to 41

1* to 3-46* 1J to 3-46*

AERONAUTICAL SOCIETY

The velocity and consequently the force of the plane are
assumed to be constant during the stroke ; and as a cushion of
resistance equal in extent to the area of the plane must be
formed during translation for every shift ®n to new air, we
have the whole work done by the plane in one second, equal
to its constant or uniform force, by the whole extended
area of resistance that sustains compression in that time ;
or equal to the sum of its constant or uniform force per unit
of area, on as many units of area of air resistance, suc¬
cessively undergoing compression, as the air path travelled in
the given “time contains ; so that, employing the above inertia
ratios >8 a?d 41, with their respective fall motions 6-56ft.
and 2* 18ft. to represent the fall motion to which the compression
of each single plane area of cushion is due
£‘2 -96

8~ >< g-^'g ~~ 0‘431b. for the 20'5ft. velocity; and

7'63

41 x 2-18

rr 0*081b. for the 11 '85ft. velocity.

In natural gravitation free from air resistance, a falling
body would require only 0637 sec. to develop 20'5ft. velocity.

As we assume, however, that the body does not fall, and
therefore does not acquire energy, but that the inertia force it
would develop if allowed to fall appears in the air that resists
the oscillating or rotating planes to which the falling motion has
been transferred, we take the translated stroke in its relation
to the stationary sustaining stroke, the sustaining force in
which we found to be equal to the gravity of the weight
supported.

If, however, the translated stroke, rated for 1 second, be
taken in relation to the natural fall of the weight, we take for the
20'5ft. velocity one-eighth of 1 second for the time of action

OF GBEAT BEIT AIN.

of the weight on a single cushion of air ; and the mean force
developed in 3\51bs. weight falling free from air resistance in
one-eighth second would be 0*431b.

The velocity of the fall here starting from zero is uni¬
formly accelerated; whereas, we assume the velocity of the
sustaining plane to be constant, so that we may take the mean
energy of the weight, which gives us a fall of about 0‘124ft.
with energy about 0"431b.

Regarding the 1 1 *85ft. velocity, the work the S’51bS.
weight would perform in an aotual free fall of 2 • 18ft. would
be 763 ; and, supposing the velocity, transferred to the plane,
were by reason of resistance to become uniform at this point,
and further, that the plane with its 0 -0851b. inertia force would
here begin successively to strike the particles of the air of
resistance on the path of translation, so as to develop in
them successively the constant inertia force of '0 '0851b., the
actual energy it would thus develop in the air would be equal to
2-18 X 0*085 = 0-1853; and 7-63 -b 0-1863 = 41 times.
If, however, we take the simple inertia force of the weight
at the given velocity per second, and not the work done or
accumulated, we then have for the 3-51bs. weight 1 -29Ibs. inertia

1 *00 SBC

force; and 0-085 : 1-29 :: — — — ' : 368 sec. ; that is, the

0-0244 second time allowed per lineal foot in translation of the

plane 1ft. square is in the .same ratio fo. 0-368 sec. as 0 "0851b.

inertia force of plane is to l-291bs. inertia force of weight : so that

0-368 U>- H>-

— = 15-08; and 15-08 X 0-085 = 1'29, in the space
0-0244

of time the weight, if falling freely, would require to develop

the given velocity of the plane ; and this is at the rate of

1-00 lb8-
■ ■■ = 2-72 X 1*29 = 3-5 for 1 whole second.

0’U\>O

AERONAUTICAL SOCIETY

The plane with its vertical pressure of sustaining resistance
has to be deflected horizontally along the path of translation ;
then, as 2*696 X 41 = 110*5 units of work done upon the air
in the stationary stroke; so 0*6797 X 20*5 X 8; and
0.23 X 11*85 X 41, respectively, give approximately the same
work in 1 second, neglecting differences due to the co-efficient
of resistance independent of velocity ; so that, as the inertia
force developed vertically is represented by that of the vertical
pressure on the sustaining plane, we have only to suppose the
plane with this pressure to be carried the two distances, vertical
and horizontal, to get the external work done upon the air in
1 second. In the resultant we have the two motions joined
but have the energy of the vertical stroke acting with full force
along the whole length of the space of translation.

The velocities are here assumed to be developed ; and to
bring the work done upon the air into just relation to the work
in gravity performed by the 3*51bs. weight allowed to fall 1
second, and which the former has to balance, we employ the
velocity that would naturally be developed in 1 second, assumed
then to become uniform, and 3*5 X 32*18 = 112*63 units of
work.

The air pressures due to velocity of plane are according to
Morin’s Rule.

In the case of a bird, the energy of the weight acquired
in a vertical fall, would be used to give velocity to the trans¬
lating deflexion, free from wing stroke ; but this would be only
where there was room for the necessary convexity earthward
of the curve the path would lie in.

The vertical pressure on the wing would decrease with the
lessening vertical momentum of the weight. In a horizontal
line of flight, the air resistance developed on the wings takes
the place of the force of gravity that would be developed in the
weight if left free to fall ; so that in travelling forward, the

OF GREAT BRITAIN.

wings distribute the equivalent to this force of gravity on an
extended bed of air ; and the quicker the flight, the more
extended is the bed of air resistance, in a given time, and there¬
fore the less the sustaining resistance required per unit area of the
extended bed ; consequently less pressure is needed upon the
unit area of the wing. The weight can cease to exert pressure
on the wing only at such moments as correspond to the sum¬
mit of the rise of a body shot up into the air. The flight of
some birds shows a quick succession of such summits, with low
elevation from the points between on the undulating path of
flight.

In the case of a bird swooping downward, and then in the
path of a curve convex to the earth, employing the momentum
it has acquired in the fall to carry it upward again, the wings
will be inclined tangentially to the curve, so that if the curve
be regular, perpendiculars to their faces would all meet at one
point inside the curve.

From tabular records of experiments made by M. Didion
in conjunction with Morin, and recorded in Bennett’s “Morin,”
we extract a few of the quantities relating to the descent in
air of a plate 1*196 square yards, area, = 10*7641 square
feet ; the quantities relate to the latter part of the fall.
Columns S, T, and V, are derived directly from the table given,
and the quantities in the other columns are got by process of
simple subtraction.

AEBOtfAtfYICAL SOCIETY

Let S be the whole space fallen from the starting point
to thfe point of observation ; T the whole time of the fall to
that point ; V the velocity acquired on reaching each successive

point;

the ratio of acceleration the successive intervals be

tween the observed points ; v, t, and s, respectively represent
the velocity, time, and space, of these successive intervals.

tfo. & TV s tv —

1.. .11*975ft.... 1*187... 18*21

2.. k14*429 „ ...1*346.. .19' 5...2*454...*159...1*29...8*113

3.. .17-992 ,, ... 1*493... 20*73. «.3*563... *147.. .1*23... 8*867

4.. .20.991.. ... 1*636.. .21’75.. .3*000. ..*143. ..1*02. ..7*133

5. . .23*989,, ...1*771.. .2,2* 5...2*988...*135...0*75...5* 55

6.. .26*988 „ ...1*910. ..22' 8,..2*999...*139...0*30...2*158

7. . .29*439 „ ...2*304. ..22*86... 2*451.. .*124. ..0*06. ..0*484

17*455

Thibault, experimenting with two planes, each of 0*12323
square yards area, and at the end of arms each measuring
8*9 7ft. mounted on a horizontal axle, and motion given in all
cases by the descent of a weight of 8*82lbs. got results repre¬
sented by the proportionate quantities in the following table.

In the table as given by Thibault, the quantities are
expressed in yards and lbs. ; but, to exhibit how nearly the
sine of the angle of inclination gives the measure relatively of
the resistance, up to 50°, we find it convenient here to express
the quantities in the proportion they bear to 1*0 for 90° which
is the angle when the plane is perpendicular to the direction of
the rhotidn, and ’therefore the angle of maximum resistance.

As the motive power employed to move the axle with its
curves and planes, was in all cases produced by the descent of

OP GREAT BRITAIN.

a weight of 8-821bs. it followed that the less the resistance on
the planes, the greater the velocity of revolution ; hence, in
the table, the decrease of the resistance is in inverse proportion
to the increase of the velocity ; but, as the decrease of the
resistance is owing to the lowering of the angle of inclination
from the maximum 90°, the area of the plane being reduced
thereby from its full value 1*0 for 90°, to a value given by the
sine ; so that, at every change of angle, and consequent change
of velocity, as the value of the area is altered, we can most
readily exhibit the differences in resistance by the differences
in velocity simply.

The column V gives the simple velocity in yards per second ;
and the column V2 the velocity in yards squared.

In the column aV2 to exhibit the decreasing resistance
in relation to V 2 we make V 2 for 90° — 1*0 ; and divide this
1-0 by the successively greater quantities V 2 of the lower
angles, to get their inverse ratio, the ratio thus expressed
decreasing approximately with the decrease of the resistance per
yard of velocity.

The column A gives the sines of the angles, and conse¬
quently what is termed the perpendicular projection of the
inclined plane, or the value of the area of the plane when in¬
clined, as a displacing area.

In column B the ratio of the resistance to the square of

the velocity for 90°, thus —

C for 90° = Q‘1563l^l = 0 -020631b. per square yard of
V2 for 90° 7-5735 yds.

velocity is represented by 1 '0 ; and the lower resistances for the
greater velocities due to the angles below 90 are divided by
thin 1-0, to get the proportion they bear to the 90° maximum

In the column C, the resistance, = 015631b. proportioned
to V2 for angle of 90 is made 10; the lessened quantities

aeronautical society

represent the proportion that the lessened resistances bear to
this 10.

In the column D the actual resistance = 0'1661b. for the
given area and velocity at 90° is made I/O. If the ratio of
resistance to displacement area represented by the sine were
uniform, the quantities for the successive angles would be 10
uniformly, increase of V 2 compensating for loss of projected
area.

Column E gives the rate of the resistance per square yard
of displacement area, represented by the sine of column A, and
per yard of velocity ; thus, as the actual area of the plane was
0*12323 square yard, we have
1000 square yard

0-12323

= 8-114 times, and

B X 8-114 = 002063 X 8-114 = 0167371b. for E at 90°

The fluctuations occurring between 90° and 50° are
evidently due to mechanical irregularities in the working of the
apparatus.

Column E shows readily where what, for shortness, may
be termed slip, begins sensibly to reduce the ratio of the resist¬
ance as the decreasing angle approaches 0°; the column of
sines the while representing the air displacement value of the
inclined plane surface.

It will be seen that in angles below 50°, the rate of resist¬
ance declines rapidly.

The quantities that head the table, with the exception of
the 1*0 of column aV2 are in lbs. and yards as given by
Thibault, and are for the maximum resistance for 90°.

The observations were taken when the resistance of the
air on the inclined planes, so balanced the motive power of the
descending weight, as to make the velocity uniform ; and
column T gives the time in seconds taken to make 20 uniform
revolutions of the axle with the planes at the given angle.

OF GREAT BRITAIN.

V 3

aV3

Time
of 20
revolu¬
tions.

Angle

Vel,

yds.

VeL

yds.

Ratios

Sines.

Ratios
Resist¬
ance
to F*

Resist¬
ance
propor¬
tional
to F*

Total
actual
resist¬
ance on
project¬
ed area.

Resist¬

ance

per sq.yd
projected
t.e.,as per
sine and
per yard
velocity.

secs.

yds.

yds. sq.

sq. yds.

lbs.

68-40

90°

2-752

7-5735

1-000

0 12323
1-00

•02063

1-00

01563

1-00

01660

100

O' 16737
100

67-90

80°

2-772

7-6839

•9856

•9848

•9844

•9987

•9988

0-9995

65-56

70°

2-828

7-9973

•947

•9396

•9442

•9968

•997

1005

62-47

60°

3-014

9-8041

•8337

•8660

•829

•9942

•9945

0 957

60-25

50°

3-124

9-7593

•7760

•766(

-7697

•9923

•9927

1-005

52-83

40°

3-563

12-6949

•5965

•6427

•587

•984

•985

0-913

43-00

30°

4-378

19-1668

•3951

•5000

•3805

•9629

•965

0-761

30-50

20°

6-173

38-1059

•199

•3420

•1847

•929

•9331

0-540

24-50

15°

7-683

59-0284

•1283

•2588

•1076

•8407

•850

0-416

19-00

10°

9-91

98-2081

•0771

•1736

•0552

•7184

•735

0319

Employing the lb. and yard quantities given for 90° at
the head of the table, we will here show their mutual relation,
and will distinguish the several quantities by the letters that
head their respective columns : thus —

AV2 E = C.

A V2 E

0-12323 X 7-5735 X 0 16737 = 0-1563 = C.

?W5 = °-°2063 = 5

1-0 sq. yd.

X B = E

1-0

0-12323

X 0 02063 = 0 16737 = E

AEBONAUTIOAL SOCIETY

IV.

Any solid body while in flight, tends to leave a more or
less partial vacuum behind, according m the speed ; and, as the
removal of one unit of pressure on the rear face, leaves one
unit of pressure on the front face unbalanced, and therefore
free to act backward, the impelling force has to expend
part of itself in overcoming the backward tendency ; but
even in the utmost velocity attained by fleet birds, the
unbalanced pressure is inappreciable, and may be neglected
in the case of mechanical flight, seeing that the rule
given for the determination of resistance to planes in motion
is derived from the results of experiments in which this back¬
ward tendency was in action. We may however explain the
reason of the pressure on the rear face being less than the
normal atmospheric pressure.

Air rushes into a vacuum with the velocity due to a body
falling freely in space, from the height of a column of air that
would give the nearly 151bs. static pressure per square inch at
the sea level, assuming the density of the air in all that height
to be uniform with the density at the sea level : thus, the
weight of one cubic foot of air 62° Fah. is 00761 lb., and the
height of column of air required is about 27835 feet, = H ;
then </# X 2 g = velocity at end of fall, which gives 1338
feet velocity of air entering a vacuum, when the barometer is
at 30.

We will suppose a body, the front face of which measures
1 square foot in area, to be in motion, and will assume for it
the velocity of 44ft. per second, equal to 30 miles an hour,
with the pressure of 3-1049lbs. per square foot of area.

6T GRKAT BRITAIN.

The static pressure of the atmosphere being nearly 151bs.
per square inch, is equal to 2169lbs. pressure per square foot,

and

21601bs.

3-10491bs.

= 696 times the atmospheric pressure exerted

on a vacuum exceeds the pressure of resistance to the motion
of the body at 30 miles an hour, or 44ft. per second; and

1338

~l4~

= 30 -4 times, so that, as the air is capable of rushing

with 30 ’4 times the velocity of the body, it follows that, if the
body moves 1 unit of distance, the air will dose in behind ex¬
pansively, and have 30'4 — 1*0 = 2 9 ‘4 times velocity still in
reserve undeveloped; and 1338 — 44 = 1294ft. per second

reserve velocity ; and

1294

8d)2

161 ’34 = the square root of the

height of column representing the height of fall for the reserve
velocity, 161/342 = 26030‘59 feet fall IP, that would generate
the reserve velocity.

Now it is clear that as the reserve velocity here is unde¬
veloped, the force of the developed velocity can be no more than
is due to 44ft. per second ; and, as the body is assumed to be
receding at that oonstant rate, and further, as the force which
is following behind to fill the vacuum is satisfied with the
simple tilling and the restoration of the atmospheric pressure
behind, to balance that in front, and can add no impetus to
the receding body, else would the force in the receding body
be augmented beyond the power that produced the vacuum,
any increase of velocity occurring in the receding body can only
simply develop more of the reserve velocity in the air closing
in behind, until, when the velocity of the body and of the air
behind are equal, the air has done its utmost ; and, if the body
increases its speed still more, as in the case of a gun ball, the
air cannot keep paee with it, a vacuum is the consequence, and
the body has now to sustain on its front face the unbalanced

AERONAUTICAL SOCIETY

pressure of the air at the rate of nearly 151bs. per square inch
of perpendicular surface, in addition to the resistance its velocity
excites by the compression of the air on its front face.

As shown in the reduced height Hl of the air column to
which what we have termed the reserve velocity is due, when
the air has expended 44ft. of its 1338ft. full vacuum rate per
second, the pressure per square foot appearing in the elastic cur¬
rent, that in the manner of expansion of the surrounding air
is closing in behind at this lesser rate, can be no more than
that due to H1 equal 26030\59ft. ; the difference will have
expended itself in motion ; and, when the full rate of 1338ft.
has been reached for the absolute vacuum, the original
whole pressure of 21601bs. per square foot at the starting
ing point, will likewise have expended itself in motion, else
would it have power to keep pace with the receding body at a
velocity beyond this.

The height of fall that would give the determined velocity
is the height of the column of air whose weight gives what is
termed the atmospheric pressure ; but we have this atmospheric
pressure appearing in the vacuum and acting with expansive
elasticity in the manner of the elasticity of a depressed spring
when the depressing resistance yields to it.

The air enters the vacuum equally from all directions with
the parts nearest to the vacuum made thinner by the imme¬
diate expansion, than those farther away in the body of the
surrounding air, but if the body be moving horizontally at a
velocity of say 1400ft. per second, it is clear that, though the air
can readily close in behind on transverse lines radial to the axis
of flight, the rear face of the body in motion, receding 1400 —
1338 = 62ft. per second faster than the air can fpllow along
the axis of flight, will be free from pressure.

It is evident, however, that a vacuum can never be formed
except at velocities far beyond what can ever be attained by

OF GBBAT BBITAIN.

wings ; and as these high velocities belong to gunnery rather
than to aerial locomotion, moreover, as the co-efficient of
resistance is found sensibly increasing with the velocity in high
velocities, moderate velocities with the co-efficients relating
thereto need alone be here considered.

In Fig. 3, let eg be a plane inclined and in motion in the
direction indicated ; and let the points a, b, and c be points
successively reached by the leading edge in equal intervals of
time.

Fig. 3.

- ■ - 3*

We will suppose the plane to have started from S at a
given uniform quick motion, and on reaching a to have dis¬
placed a volume of air from S to e, in volume equal 1, and with
1 unit of force. On reaching b, a similar volume of air equal
1 will have been displaced from a to h, while the first volume
will have been displaced further from e to /; and as the motion
is uniform, and Se, ah, ef, &c., are all similar spaces of displace¬
ment, it is evident that the displacement force in ef, will at f
be equal to 2 units =. Se + ef-, and at g will be equal to 3
units ; while the force expended on the displacement of the
volume from b to j, will at j be only 1 unit, same as at e and
at h,

Ai$BON ATTTIffi AL SOOIETY

At g however, the units of force are due to 3 corres¬
ponding units of time ; at f to 2 units, and at e, and h, and j
to 1 unit of time only ; but as the spaces Se, ef, fg, &c., are
equal, and correspond to the similarly equal spaces of area,
ae, bh, cj, &c., we have 1 unit of time and of force to each
unit space of area.

The unit volume of air on acquiring the given uniform
velocity at e, does not within itself develop more than the
given unit of force ; but the resistance to displacement of the
air beneath it, and against which it is pressed, develops
the second unit of force due at f in a second volume.

It is apparent that the stratum of -free air here displaced by
compression, must aot differently to a similar bulk confined ;
the angle of inclination of the plane is assumed to be low, and
the velocity of flight to be rapid, to give short time for the
compressed air, by the effort of expansion to overcome the
inertia of the air beneath the path of flight.

We assume that there is no lateral relief, and that
the only direction of displacement is perpendicular to the face
of the plane.

Allowing that there be 3 volumes of air at g, each
possessed of 1 unit of force in elastic compression, the expan¬
sive reaction when the 3 volumes are liberated to the rear of
g, will carry the wave of expansion farther than the wave from
a single volume set free to the rear of e ; and upon this
expansive reaction would depend the forward impulse on the
flexible plane of Fig, 1.

We have assumed 3*51bs per square foot of wing plane for
the weight to be sustained. This proportion of weight to area
is in excess of that observed in birds, and would necessitate
greater velocity of flight, which would be more readily attained
if the greater burden were relatively in smaller bulk than the
lesser burden with its lower velocity.

OF GKfcAT BBITAIH.

The bulk of a man weighing 1541bs. is, roughly, about
4 cubic feet; and a bulk of air of this weight is about 1909
cubic feet at 32° Fah.

A cube measuring about 1 -59ft. length, depth, and breadth,
would represent the man ; and a cube measuring 12 -4ft. on the
side would represent the air; and 1909 — 40 = 477 times
the volume of air exceeds the volume of the man.

Were the man able to expand his form so as to occupy
the 1909 cubic feet equivalent volume of air, he might float
with the same motion as the air surrounding him ; but, if
dissatisfied with that passive motion, he sought to transport
himself afloat from place to place independently, he would find
that the air sought to be displaced in this motion of his own,
had as much gravity as he himself possessed.

If, with this 1909 cubic feet expanded volume and weight
still equal to the air equivalent, he shaped himself say into
winged form, the winged form would present less frontage for
the air to act upon in resisting forward motion ; but, the out¬
spread area of the wing-planes would now present so much
more surface for air currents to take hold of, that, if he
purposed going to any particular place, he would have to wait
till the wind went that way likewise.

If, with his weight still equal to the air equivalent, but
his expanded form contracted into half the space of the air
equivalent, that is, from 1909 to 954*5 cubic feet, his buoyancy
would be gone ; and as he now occupied only half of the
equivalent air space, only half of his 1541bs. weight would be
supported by the surrounding air; the other half, equal 77lbs.,
unsupported would take him direct to earth, with his descent
retarded only by the resistance to displacement due to his
contracted or half volume form.

If, however, while up in air, he could give motion to this
contracted form, the momentum of the 771bs. free weight

AERONAUTICAL SOCIETY

would enable him to cross a current of air with less side drift
than if his form were expanded to. the 1909 cubic feet equiva¬
lent volume, in which his full weight of 1541bs. would be
■wholly buoyant; because the 77lbs. free weight would here
relatively be weight without form for the resistance of the air
to act upon ; and the air in resisting displacement, would have
only the contracted or 954*5 cubic feet volume, representing
the 771bs. floated or buoyant weight to deal with ; thus, we
may suppose A in Fig. 4 to represent the 1541bs. wholly buoy-

Fig. A

CD cC

ant ; and B to represent 77lbs. buoyant, with the 77lbs. free
weight enclosed in it as C.

JAMES ABMOUB.

OF GREAT BRITAIN,

NOTES FROM FRANCE,

T. J. Bennett.

England ia not the only country that can boast of an
Aeronautical Society, for France possesses one which is worthy
o. the land where Aeronautics first saw the dawn. In 1863
all Europe was roused and interested in the solution of the
problem of aerial navigation, by the energetic appeals of
MM. Nadar and La Landelle. An Aeronautical Society was
founded, and for a year or two flourished ; but as nothing
practical was forthcoming, it soon languished and died. The
present Society was founded in 1868 by Dr. Hureau de
Villeneuve, to whom, in a great measure, its present flourishing
state is due. This energetic gentleman also started a monthly
magazine, called I'Aeronaute, which has continued to appear
regularly ever since April, 1868, and is the only instance in
which a journal specially devoted to aeronautical science has
been a continued success.

The Society meets twice a month to read and discuss
papers on every subject connected with aeronautics. They also

AEBOSAUTIOAXi SOCIETY

possess an excellent library of aeronautical works, and a museum
of aerial models, which is open daily, at the residence of
Dr. de Villeneuve.

A summary of the transactions of the meetings is pub¬
lished in I'Aeronaute, along with the most important papers
read.

Many of the members of the Society are passionately
devoted to the solution of the problem, and have spent much
time, ingenuity, and money in experiments, with considerable
success. Most prominent amongst them is M. Penaud, who has
succeeded in constructing models that will fly on three different
principles, viz.': — the vertical screw, an aeroplane with automatic
rudder, and a mechanical bird with flapping wings. We
purpose giving a description of these machines, with illustra¬
tions, thinking they will be of interest to the members of our
Society.

We will begin with the h&icoptare, or ^vertical screw, as
being the most simple and possessing the greatest antiquity.
The first machine on this principle was constructed by
MM. Launoy and JJienyenu, and presented to the French
Academy in 1784. It consisted of two vertical screws super¬
posed, turning in contrary directions, fhe motive power was
a whalebone bow attached to one of the screws, two strings
proceeding from its extremities to the vertical shaft of the other
screw, round which they were wound. The reaction of the
elastic bow produced the contrary revolutions of the screws.
This little model rose to the ceiling, lifting a load equal to its
own weight. Although this was the flrst working model of a
helicoptere that we know of, the principle had been proposed
as far back as 1768> when Paucton in his treatise on the
Theorie de la vis d’Archimede describes a machine provided
with two screws which he calls a pterophores. One of the
screws r^as fof ascension, the other for propulsion. Sir Qeorge

QF GRSAT BRITAIN.

Cayley also constructed a machine similar to that of MM. Xiaunqy
and Bienvenu in 1795, which he described in Nicholson’s
Journal for April, 1810. Deghen in 1816, Oittoris Sarti in
1823. and Dubochet in 1834, all proposed and constructed
models for flying machines on the vertical screw principle. The
idea then seems to have died out till, in 1863, MM. Ponton,
d’Amecourt, da la Landelle, and Nadar drew the public attention
to the application of the screw to aerial navigation, by exhibit¬
ing several models, driven by clock springs, which ascended to
the height of from nine to twelve feet, with graduated weights
attached to them. It is is only due to our fellow-countryman,
Mr. Bright, who is, I believe, a member of this Society, to
state that, in 1859, he took out a patent for a machine to be
sustained by vertical screws, and constructed a model, which is
to be seen at the Patent Museum, Kensington. Many others,
including Mr. Bourne, the well-known engineer, have also con¬
structed flying models on the same principle. Nearly 40 years age
Mr. Artingstall, of Manchester, constructed a machine driven
by compressed air. but did not succeed in making it self-
supporting. Encouraged by the success of his spring models,
M. d ’ Amecourt had a small steam engine, with an aluminium
boiler, constructed and provided with a pair of vertical screws,
but it was not very successful, only lifting about a third of its
own weight. This model was shown at the Exhibition held
at the Crystal Palace in 1868.

All the spring models which we have described were so
delicate that they were often broken on descending to the
ground. Their flight only lasted a few seconds, and partook
more of the character of an aerial somersault than true flight :
for they had no sooner commenced to ascend than the spring
had run down, and the screws stopped. These defects struck
M. Penaud, who made many experiments to overcome them.
Whalebone and 6teel springs only store up a very small power

AERONAUTICAL SOCIETY

compared to their weight, so he decided to use indiarubber,
which is far more powerful ; but if the rubber is used under
tension it requires an immensely strong and heavy framework
to stand the pressure: M. Penaud therefore determined to
use its elasticity under tension, which greatly simplified the
mechanism. It also possesses the remarkable quality of
developing an almost uniform power without the intervention of
compensating machinery. The immense advantage in employ¬
ing rubber in the place of steel springs, is evident by comparing
the following data : —

A steel spring weighing 1 kilogramme (21bs. 3^ozs.) will
only store up a power of 73 foot lbs., while the same weight of
rubber stretched to six times its natural length will give out in
contracting a power of 3660 foot lbs., that is to say fifty times
as much. But in order to utilize the tension of rubber it would
require a mechanism more or less complicated, which would
absorb part of the power and be of considerable weight. By
using the rubber under torsion the mechanism is extremely
simple, the elastic being connected directly to the screws ; but
it has the disadvantage of furnishing only a power, of 1300 foot
lbs. per kilogramme. The power developed under torsion is thus
greatly inferior to that given off under tension ; but this
inferiority is in great part compensated for in small models by
the simplicity of the mechanism and the uniformity of the
power given off.

M. Penaud first applied his new motive power to a
helicoptere or vertical screw which is represented in Fig 1.

This model was constructed and shown to the French
Society in 1870. It consists of two screws superposed, turning
in contrary directions ; their distance apart being maintained by
two little strips of wood between which is placed the rubber.
One end of the rubber is attached to the frame which carries
the top screw, and thus turns it by reaction ; the other end is

OF GBEAT BRITAIN.

fastened to a hook on the extremity of the shaft, to which is
attached the bottom screw, thus causing it to revolve by direct
action in a contrary direction to the top one.

Fig. 1.

In order to fly the model, the frame is held by the left
hand and the lower screw turned by the right one in a contrary
direction to that which is requisite to support the machine.
When the rubber is sufficiently twisted, it is only necessary to
abandon the apparatus to itself. It will then (according to the
proportion of the screw area to the weight) rise like an arrow
to the height of 50ft.; glide obliquely in describing large circles,
or else, after having mounted to *he height of 8 or 9 yards,
hover in the same place for 15 or 20 seconds, and even for 26
seoonds.

M. Penaud has also experimented with a metal screw
rotated by a string after the manner of the well-known toy.

AEROKAtmcAl. SOCIETY

the flying top. The late M. Babihet, the celebrated mathe¬
matician, stated some years ago in a lecture on Aerial
Navigation, that he had seen one of these toys fly over the
cathedral at Anvers ; but M. Penaud has surpassed this feat
by means of a screw well polished and silvered. The
inclination of the blades was only from 3° to 5° from the
horizontal. When started in a slight wind it will rise slowly
for 4 or 5 yards and then go off in a horizontal direction with
increasing velocity for 60 or 70 yards. It then asgends rapidly,
often disappearing in the distance, when in a few seconds it
will rfeappear approaching its starting point at a height of 60ft.,
and With the rapidity of an arrow dash over the experimenters’
head to the distance of 100ft. in the opposite direction. The
total time occupied in this erratic fight being about 20 seconds.
This toy is rather a dangerous one to fly, but the experimenter
is well repaid for the risk run by its marvellous flight, which
demonstrates that a simple screw suffices for the support, the
translation, and the equilibrium.

A few experiments have been made in France with large
screws driven by manual power. In 1863 M. La Landelle
constructed a screw 20ft. in diameter, with which he was able to
support a weight of 321b. when the machine and man were
placed upon a weighing bridge. He afterwards tried it with
the screw free to move in a vertical line oh the shaft, after the
manner of Mr. Wenham’s screw, described in the First Report
of this Soeieiy, when he found it would rise along the shaft
with a weight of more than 1001b. attached to it. This weight
evidently cannot have been supported by the air, for in the
former experiment he was only able to lift 321b. The phe¬
nomenon was caused ho doubt by some peculiar action of the
shaft on the screw. The above experiment would tend to
throw* some doubt Oh the reliability Of the results given by
Mr. Wenham’s screw.

OF GREAT BRITAIN.

Two years ago M. Benoir, a member of the French Society,
experimented with a screw 15ft. in diameter, with which,
by the action of his feet, he was able to lift a weight of
26lbs. The screw was two-bladed with an increasing pitch,
the angle of inclination being 3° at the front edge of the blade
and increasing to 30° at the back edge. The two blades cover
the entire area of the screw and have a deep rim suspended
from them to prevent the air being driven from the circum¬
ference by centrifugal force. M. Benoir estimated the power
he developed was about one-fifth of a horse power, but this was
considered, by the members of the French Society present at
the experiment, to be considerably below the real power exerted.
As the screw was driven by the feet after the manner of a
velocipede, the body being in a good position for exerting its
maximum effort, the power delveloped was undoubtedly nearly 1
horse power. A man running up a pair of stairs is able for a
few seconds to exert two-horse power, and mounting a ladder
placed vertically, by the help of his hands, an ordinary man can
do the work of 1^-horse power. These facts have been deter¬
mined by experiment.

As we have now exhausted the subject of the vertical
screw we turn to the aeroplane. Sir George Cayley, in 1810,
proposed a machine which consisted of a flat surface inclined
up at a slight angle, and propelled horizontally by a screw
propeller ; but he did not go further than prove its practicability
on paper. Henson, in 1842, patented a macnine on the same
principle, and his fellow-workman, Mr. Stringfellow, succeeded,
in 1847, in making a small steam engine, provided with an
aeroplane, fly. In France M. du Temple, in 1857, and
M. Jullien, in 1858, constructed small models which were
successful. M. Jullien ’s model weighed 36 grammes (l^oz.),
and its sustaining planes were 40 inches from tip to tip. It
was propelled by two two-bladed screws, the motive power being

AERONAUTICAL SOCIETY

a piece of elastic under tension. The machine flew for five
seconds, during which time it covered a distance of 40ft. But
all the above models flew by accident, there being no special
means provided for maintaining the equilibrium fore and aft.
This problem M. Penaud has solved by means of his automatic
rudder. Having proved the power of the vertical screw he
thought of applying his rubber to . a machine on the aeroplane
principle, but was for some time baffled by the difficulty of
maintaining the equilibrium. At last the idea occurred to him
of placing a small horizontal rudder behind the sustaining
planes, and inclined at a small angle to it. It succeeded
perfectly. Its mode of action is as follows : — The centre of
gravity of the machine is placed a little in front of the centre of
pressure of the aeroplane, so that it tends to make the model
descend an incline ; but in so doing it lessens the angle of
inclination of the aeroplane, and the speed is increased. At
the same time the angle of the horizontal rudder is increased,
and the pressure of the air on its upper surface causes it to
descend ; but as the machine tends to turn round its centre of
gravity, the front part is raised and brought back to the
horizontal position. If owing to the momentum gained during
the descent the machine still tends upwards, the angle of the
plane is increased and the speed decreased. The angle of the
rudder from the horizontal being reduced, it no longer receives
the pressure of air on its superior Burface, the weight in front
reasserts its power, and the machine descends. Thus, by the
alternate action of the weight in front and the rudder behind
the plane, the equilibrium is maintained. The machine during
flight, owing to the above causes, describes a series of ascents
and descents, after the manner of a sparrow. The lateral
stability is easily obtained by slightly inclining the aeroplanes
upward from their bases, or even by just turning up their tips.
The machine is represented in Fig. 2, and after what we have

0T GBEAT BRITAIN,

AERONAUTICAL SOCIETY

said about the helicoptere its action is seen at a glmce. It
consists of a rod 20 or 30 inches long, which constitutes the
main frame. To its front end is attached a small hook, and to
the back one a bearing for the screw axle, which is also ter¬
minated by a hook. Between these hooks the rubber is
stretched. The screw is two-bladed, to prevent injury to it on
striking the ground, and is 8in. in diameter. In the illustration
it is shown at the back part of the machine, but it has been
placed in the front with equal success, only in the latter
position it is subject to be damaged on striking an obstacle.
Some models have been made with a pair of screws turning in
contrary directions, to prevent the reaction of the elastic turning
it over sideways ; but this is easily prevented by fixing a small
piece of lead to the outer extremity of the aeroplane. About
the centre of the rod is placed the sustaining planes, which are
made to slide along it to any position. The angle of either
plane can also be altered at will. A little distance in front of
the screw is placed the horizontal rudder, which is inclined
upwards. The length of the plane is from 18in. to 2ft., by
about 4in. in width. Its ends are slighly turned up, as are
also those of the rudder, in order to maintain the lateral
balance. The centre of gravity is a little in front of the centre
of the aeroplane. A model constructed on the smallest of the
above proportions weighs 16 grammes (l^oz.), of which the
elastic represents aboc „ one-third. In order to fly the machine
it is necessary to wind up the elastic by turning the screw
about 240 times. Upon abandoning it to itself, in a horizontal
position, it will fall about two feet, but at the end of this
descent, having acquired velocity, it rises, and flies at a height
of eight or ten feet from the ground for about 130 feet. This
distance is accomplished in 11 seconds. Some of the large
models have even flown for 200 feet, supporting themselves for
13 seconds. During the whole of the flight the horizontal

Of GFBEAT BRITAIN.

5 9

rudder maintains the equilibrium ih causing it to describe
isochronal ascents and descents. When the rubber has nearly
ran down the apparatus descends gently to the ground, taking
an inclined course, and preserving its upright position. The
mean speed is 12 feet per second, which is fully equal to that
of any insect provided with the same proportion Of wing surface.
If the model is started against a wind equal to its own velocity
it will remain suspended in the air similar to the hovering of a
bird. Great practice is required to start the machine with the
wind on the beam, as it gets under the plane and tends to turn
the model over sideways. When flown with the wind it must
be thrown forward like a dart. Its velocity then of course is
equal to the sum of its own and that of the wind. If, in
experimenting, the model pitches forward on its nose, it is only
neeeSSary to slide the aeroplane further forward on the rod.
If it still pitches turn up the horizontal rudder slightly. A
little experience will soon determine the proper angle. Each
plane consists of a long quill, to which the stems of smaller
feathers are attached by means of pins pushed through the
main quill and down the centre of the small one. The whole
is covered with gold-beaters’ skin. They should be inclined
upwards at an angle of about 7°. M. Penaud presented his
first aeroplane to the French Society in 1871, since which
period he has often exhibited it to the public. From calcula¬
tions and experiments with this model he thinks that one-horse
power would support about 851bs. He has also succeeded in
constructing boomerangs in steel and wood, after the model of
the Australian ones, which fly equally as well. Their peculiar
flight is owing to their shape, which is that of a descending
screw.

The following details of an aeroplane on a scale large enough
to carry a man, now in course of construction at Brest, by
M. Du Temple, may be of interest. It consists of a plane 40ft.

AEBONAUTIOAL SOCIETY

from tip to tip, and two rudders, one horizontal and the other
vertical. The frame is made tubular and of steel, the whole
being mounted on three light wheels. The motive power is a
hot air engine ; the two cylinders 18in. in diameter, being, con¬
structed of thin steel, strengthened by rings of the same metal.
The cylinder covers carry the piston guides, and are also provided
with safety valves. The bottom of the cylinders are exposed to
the fire, the fuel being petroleum. The machine is propelled
by one six-bladed screw 13ft. in diameter. The total weight
is 1601bs. The whole of the workmanship is very fine, no
expense having been spared, and when finished will cost not
less than £1200. This machine has been building for
some years, but is now nearly finished, so that we may hope
soon to hear of its “going off.”

We will now deal with the third machine ; the mechanical
bird with flapping wings. To construct a helicoptere was
comparatively easy ; to make an aeroplane less so ; but a
mechanical bird offers serious difficulties. All the accounts
that have been handed down to us of men flying with wings
are very unreliable. It is not sufficient for an inventor to say
that he has succeeded in flying, he must show proof of it ; and
I think it can be safely said that M. Penaud is the first man
who has succeeded in making a machine to fly with wings.

M. Marey, whose remarkable researches upon the flight
of birds have been published in previous reports, constructed, in
1870, some artificial insects which lifted one third of their own
weight. They consisted of a pair of wings attached to a
shallow metal basin covered with a thin sheet of rubber, similar
to those used by him for recording the movements of the wings
of birds. They were placed on the end of a balanced lever
which allowed them to rotate in a horizontal direction. Com¬
pressed air to work the wings was conveyed to the basin
through the upright that supported the lever. These insects

OF GREAT BRITAIN.

were a step in the right direction, but there still remained two
thirds of the weight to be lifted. It was also necessary to make
them carry their own motive power and be entirely disconnected
from the ground in order to show real flight.

In the latter part of 1871 MM. Penaud and Hureau de
Villeneuve, the secretary of the French Society, began to make
experiments with mechanical birds propelled by rubber. They
called to their aid M. Jobert, a clever workman, who con¬
structed the steel framework required.

M. de Vifleneuve’s theory of flight was altogether
different from that of M. Penaud’s, yet both succeeded in mak¬
ing models to fly. The former after making most elaborate
researches into the movements of the shoulder bone of the bat,
took it for his model. In his bird the axis of rotation of the
wings are oblique, the wings striking downward and forwards.
These wings, which are nearly rigid, have a conical movement
given them, and the changes in the angles of inclination of
their surfaces are entirely due to this movement. M. Penaud
on the other hand has constructed his bird after what he calls
the “classical theory”: viz. — that of Borelli, Cayley, Strauss,
Durckeim, and Marey. Id his wings the changes in the in¬
clination of the surface is obtained by the elasticity of the sail
or back part of the wing, the little sprigs that support it being
free to rotate round the rod that forms the front edge.
Eubber springs run from the back inner edge of the wings to
the centre of the rod which forms the main frame. These
springs regulate the movements of the sprigs and give the
wing its elasticity, performing a similar function to that of
the hind claw of the bat. The torsion and changes in the in¬
clination of the wings are thus regulated by the combined action
of the pressure of the air and these springs. The front edge
of the wing has a simple up-and-down movement, which the
elastic motive power transmits to it through the intervention of a

AERONAUTICAL SOCIETY

crank and two rods. When the wing is in. ita highest position
at the end of the upstroke, the rubber springs before mentioned
cause it to present its inferior surface forward at an inclination
of 15°. Upon the descent of the wing, the resistance of the
air causes the outer portion of the wing to twist into a screw
shape, the back edge being higher than the front, and thus
supports and propels. The inner portion of the wing always
remains inclined up, and acts as a kite. In the up-stroke the
whole wing supports as a kite, its surface being inclined up¬
wards, the back edge being lower than the front. The wing
is thus divided into two distinct parts, one active and the other
passive, the outer, which comprises two-thirds of the wing, both
supporting and propelling, while the inner portion only supports.
The machine is not altogether sustained during the up-stroke
so that the down-stroke has to make up for the deficiency.

Fig. 3 is 'a view of M. Penaud’s bird. The wings are
shown in the act of descending, the inner portion being inclined
forward, and acting as a kite, the outer part being inclined
backward, and propelling and supporting. The equilibrium
is perfectly maintained by the tail. This model is unable to
rise from the ground ; but upon being thrown off the hand it
descends some 2 feet, and then having acquired velocity flies
horizontally for a distance of 50 feet, rising about 8 or 9 feet
above the point of departure. The duration of flight is seven
seconds. The following are the proportions and weight of the
model : — each wing is 16 inches in length, and the total weight
is 73 grammes (about 2^oz.), thus divided : —

The two wings

• • •

Grammes.

Frame

• • •

Rubber

• • •

Tail

»•*

AERONAUTICAL society

M. de Villeneuve’s model, thanks to the peculiar motion
of its wings, was able to start direct from the ground, but
owing to the small number of strokes only rose to the height
of 4 feet, when the spring having run down, it descended, forming
a parachute. It possessed a remarkable power of rising, and
at each stroke the machine was lifted with great force. M. de
Villeneuve has since modified it, so that it will fly horizontally
for a distance of 24 feet, at a velocity of 20 miles an hour.

M. Sivel, one of the unfortunate victims of the late fatal
balloon ascent, when at Leipsic, saw a little steam bird con¬
structed by an optician of that town. It consisted of a globular
boiler that would hold about a gallon, supported upon a tripod.
In the top of the boiler was a small cylinder, with a two-inch
stroke, which worked two wings 32 inches long. The wings
were provided with valves, which opened during the up-stroke.
The boiler contained spirits of wine sufficient for 38 seconds.
This machine would rise vertically 3ft., the wings making about
three beats during the flight.

Flight has thus been accomplished on three different
principles, and the practicability of a flying-machine proved.
M. Penaud, whose opinion should have great weight, thinks the
aeroplane to be the only practicable machine ; but he fears that
it will be many years before aerial navigation will be
realised. Let us hope not.

OF GBEAT BRITAIN.

CONCLUDING REMARKS.

This, our Ninth Report, brings us very nearly to the tenth
year of our existence as a Society.

In our short review of the past it will be necessary to allude
to the fatal accident of M: de Q-roof, which resulted from his
descent from a balloon in an apparatus designed and constructed
by himself for purposes' of flight.

As this mishap might be taken as evidence of the difficulty,
if not impossibility, of accomplishing mechanical flight, a few
of the facts may be recorded.

It was stated that in a previous attempt the machine and
aeronaut were severed from the balloon at a considerable
altitude, and that at his descent he distanced the balloon and
reached the ground several fields in advance. Subsequent
evidence showed this to be an incorrect report.

At the second ascent, when the machine was detached,
the wings were seen to collapse together over head, as if the
muscular force of the legs, to which they were connected by
cords, was not sufficient to keep them extended, consequently
the fall was exceedingly rapid.

The wings measured 37ft. from end to end, so that the
leverage was very great. Had they been prevented from folding
quite back, by means of suitable stops, the descent might not have
proved fatal, though the experiment would have been far from
safe for the following reasons : — The area of the wings and

AERONAUTICAL SOCIETY

tail, as extended horizontally, was 220 square feet. The weight
of the man and machine was 3501bs. If he could not move
his wings so as to aid his support, the rate of perpendicular
descent would be 1540ft. per minute, being limited to this
speed by the resistance of the atmosphere at l'61bs. per square
foot. 1540ft. per minute is the velocity acquired at the
termination of a descent from a height of lift., an unsafe
distance for an ordinary person to fall, but the feat might be
performed by a trained acrobat without damage to himself.

It would appear, therefore, that the arrangement was
badly conceived and carried out, without regard to data or
principles, and that the position taken by the wings afforded
no support. Had they remained extended horizontally the
result would have been different, and the descent gradual like
that of a parachute.

It has been stated at previous meetings that the Society
was desirous of testing the application of the screw to a balloon
for the purpose of effecting ascent and descent. This was
recognized as a means for prolonging the life of a balloon, and
presented the only material improvement of which, in the
opinion of the Council, a balloon was to be made capable,
while floating in obedience to the direction of the wind, of
altering its altitude without parting with gas or ballast.

In a former report the advantages of such an appliance
were enumerated.

It was during the time that instructions had been given
for the manufacture of a suitable arrangement, that Mr. Bowdler
received permission to test an apparatus at the Royal Arsenal,
for the propulsion of a balloon by means of a fan or propeller
fixed to the car of a balloon. It would not have been necessary
to allude to this attempt, but for the fact that the same
apparatus combined also a propeller to raise and depress the
balloon.

OF GREAT BRITAIN.

The result was exactly as the initiated would conceive.

It may be stated, however, that the balloon of 60,000
cubic feet was large in proportion to the means employed:
Mr. Bowdler raised a doubt of success upon this account.

The first trial was made vertically. The following account
is given by Captain C. Orde Brown in the Popular Science Review,
October, 1874.

“Major Beaumont, Mr. Coxwell, Mr. Bowdler, and a
Sergeant of the Royal Engineers entered the car, which was
carefully balanced, and the first part of the programme was
commenced, the balloon being held captive. Owing to a
deficiency of suitable rope the raising was only carried out to
the height of about 40ft. instead of 150. The difficulty of
ascertaining exactly when a captive balloon is balanced, when
even a slight wind is blowing so as to stretch the retaining
rope, made the first trial a little doubtful, and after one ascent,
apparently due to the working of the propeller, a doubt arose
as to the exact balance of the balloon, which might have a
tendency to rise and only have been held down by the captive
line, which, except at very still moments, was pulled taut by
the wind acting on the balloon. It being ascertained, at a
still interval, that the balance was good, the vertical gear was
worked and the balloon again rose. The rate of ascent was
difficult to estimate, it was judged, however, not to exceed 50ft.
a minute. A positive indication of the power of the propeller
was thus obtained ; and it should be noticed that the circum¬
stances, if the rate of ascent only was measured, were rather
disadvantageous, for the weight of the line, up to the (extent
of 40ft., was gradually added to the balloon as it rose. Had
the mean rate of ascent and descent been taken this error would
be eliminated, for the descent would be favoured by the weight
of the rope from 40ft. in length at the maximum height down
td nothing at the ground. The balloon was now liberated, not,

AERONAUTICAL SOCIETY

however, until Mr. Bowdler’s vertical gear had become broken
and unable to work. The wind’s direction in the meantime
had been ascertained to be suitable by sending off a series of
small pilot balloons, and the ascent took place. The horizontal
gear, however, throughout the entire voyage, failed to give any
satisfactory results ; even allowing that the effect was perceptible,
it is impossible to lay much stress on it. Any force would
give a perceptible effect if recorded with sufficient delicacy.
There is no use in an insignificant effect unless it can be shown
that means exist by which it could be increased sufficiently to
bear a reasonable relation to the forces to which is to be op¬
posed, or with which it is expected to be compounded.”

Therefore the experiment which the Society had advocated
for years, and which it had at length determined to adopt,
having proved successful under disadvantageous circumstances
when tried by others, the apparatus ordered was countermanded.

When the balloon is used in the future for other purposes
than exhibition, perhaps this adjunct may be utilized.

Captain Burnaby, of the Council, has been in the habit of
making balloon ascents both by day and night. He recognized
the importance of determining the direction he was travelling
when out of sight of earth.

The absence of such means in the late war caused mishap
to several balloons.

In a recent ascent at the Crystal Palace he states that he
obtained the direction by dropping two parachutes, with an
interval of time between their liberation, and that by taking
the direction of a silken cord which connected the two, he
was enabled to verify his course.

During the past year the Authorities at the War Office
have been earnest in their inquiries as to the best mode of
aerial observation. The cumbersome nature of the apparatus

OF GREAT BRITAIN,

for manufacturing hydrogen gas, operates against the success¬
ful employment of that mode of inflation.

The hot-air balloon of M. Menier and Mr. Simmons
afforded to the Authorities some hope that successful ascents
might be obtained through such means. The particular
experiments may be passed over without further attention in
consideration of the fact that the Balloon was proved incapable
of inflation even in a very slight breeze.

It was found that the air could not be made sufficiently
expansive inside the balloon to counteract the force of wind
against the outside surface.

This affords another instance of the mistakes which arise
from the enthusiasm of aeronautical inventors, which causes
them to draw too favourable inferences from “Parlour Experi¬
ments,” conducted always under the absence of conditions
which attach to real work.

The idea which naturally suggests itself in connexion
with this recorded failure, is that the kite might be utilized when
the balloon could not be inflated. — See remarks upon Kites in ls<
Annual Report, page 65 ; and 2nd Annual Report, page 67.

In the “Concluding Remarks ” of the last Report some
description of Moy and Shill’s Aerial Steamer is given, as it
existed at that time.

Several months of close application in subsequent trials
resulted in the making of a new engine, and the strengthening
of various parts.

The accompanying wood cut is from a Photograph taken
in the grounds of the Crystal Palace. The engine which drives
the two wheels is contained in a case 27in. by 27-^in. by 7£in. ;
diameter of cylinder 2T25in. ; length of stroke 3in. ; tube surface
8 square feet. The axle runs right through the steam chest
with long bearings, and a tube to keep steam from coming in
contact with the axle.

AERONAUTICAL SOCIETY

Two eccentrics are formed, each in one piece with the
crank pin. The guide rods are made to serve a double purpose.
A light cross-head carries the valve rod, and the valve cuts off
the steam at half stroke; pressure of steam from 120 to 160
to the square inch.

When this engine was finished and found to work well, it
had to be fitted into a frame in order to attach it to the aero¬
planes ; and a great number of bamboo canes were used in
carrying this out. A triangular frame was made, which may
be called a tricycle -frame. The wheels were all made to go
straight forward only, and not to turn a circle. On this frame
was built up, about 4ft from the ground, the frame which
held the engine and lamps. Other frames extended from this
on each side to take the axles of the 6ft. driving wheels.
These axles are 3ft. 3in. in length, and l^in. diameter, made
of drawn brass tube, and very light and strong. A front fixed
aeroplane was fitted of 50 square feet of surface, and a similarly
• fixed aeroplane was fitted behind with 64 square feet of surface.
Both these fixed planes were set at 10 degrees from the horizontal,
and if driven at 35 miles an hour were sufficient to bear up
the whole weight of the steamer, which amounted to 2141bs.
The driving surface of the revolving aeroplanes amounted to
60 square feet.

This was erected in the Rotunda, in the Crystal Palace
grounds ; and with this engine and these revolving planes some
important experiments were tried to test the truth of the ex¬
periments, at Messrs. Penns’ Factory, Greenwich. If the old
theory was correct, it was expected that the pressure on the planes
would only amount to a few ounces per foot : if the new theory
was correect the pressure would far exceed that of the old. It
turned out, most conclusively, that the old theory was wrong
and the new theory right.

At a revolving speed of 20 miles an hour, and with the

OF GREAT BRITAIN.

pitch or angle of the planes set at 15 degrees, the pressure was
exactly one pound to the square foot. And at the same speed
of 20 miles an hour, and the angle set at 45 degrees, the
pressure was one pound and a half to each square foot of sur¬
face. These experiments were very satisfactory, and showed
clearly that the inventor was working in the right direction.

After more work, and necessarily more delay, it was
determined to try the steamer in the open. It was found that
one of the fountains at the Crystal Palace had a path round it
of a diameter of nearly 300ft., and it was determined to give
it a run round this under steam. A pole was erected in the
centre of the fountain, and two cords from the top of the pole
to each end of the steamer kept it at one uniform distance from
the centre. The gravel had been rolled and steam was got up.
The gravel however was too rough : it shook the steamer and
offered so much resistance that it had to be abandoned until a
smoother road could be obtained. The authorities at the
Crystal Palace then kindly consented to lend 8000 square feet
of boarding, and it was laid down round the same fountain.
More delays, more work, and more patient waiting, with heavy
falls of snow on the melancholy looking boards, and weeks of
public wonderment as to why those boards were laid down ; at
length steam was got up, and a good run was made round the
fountain, the -wing- wheels only acting as drivers. At this experi¬
ment a speed of at least 33 miles an hour was required in order to
make the steamer leave the ground. But, although it ran on
the boards, the friction, and consequently the tractive force
was much too heavy. It, however, attained a speed of 12
miles an hour, with plenty of steam to spare, and formed a
very pretty sight in the bright sunshine. This was the first
time that a machine weighing two hundred weight had ever
been driven by it’s own motive power by revolving planes imping¬
ing on the air.

AERONAUTICAL SOCIETY

Those used to bicycles and tricycles will know that the
latter require an enormous amount of exertion compared to the
former, and that three wheels fixed only for forward motion
offer a very great resistance to turning a circle.

Had it been possible to place the whole upon a railway
the effect sought might have been attained.

This suggestion was offered with respect to an imaginary
aerial carriage m our first Annual Report, page 66 (see
“ Concluding Remarks ”).

While the preparations for these experiments were going
on, Mr. Moy determined upon attempting vertical ascent, with¬
out the necessity of a previous run.

In the Report of the Aeronautical Exhibition in 1868,
drawn up by Mr. Wenham, occur the following sentences : —

“ Though we are still without a precise demonstration of
the power required for flight in the way that a bird flies, the
force to maintain which, in some species, must be very small,
yet we have some evidence of the power required to lift a
weight in the air by means of vertical screws. By this method
it has been demonstrated that 1001b. may be supported by a
constant force of about 90,000 foot pounds, or three-horse
power.

“Now, in the work of Mr. Stringfellow, the Society has
brought out the remarkable fact that a one-horse power engine
can be made to weigh only 131bs. ; thus showing the possibility
of obtaining flight by” the repudiated system of vertical screws,
even with the enormous expenditure of power that this plan
is known to require.”

Viscount D’ Amecourt attacked the problem with superposed
screw actuated by a small steam engine with aluminium boiler,
but as the model was a valuable one it was not set free at the
Crystal Palace in 1868. It was stated that it was capable of
raising itself to a great height. This was but a toy, however.

OF OBEAT BEIT AIN.

In pursuance of Mr. Moy’s determination new aeroplane
wheels were constructed 12ft. in diameter, and linen planes,
carefully stretched, were fitted ; the planes revolving in
horizontal orbits. These wheels came to grief, not being
strong enough ; others were made and failed, and the last
pair were made of three layers of bent wood, and up to
the present time they stand very well. The planes have been
set at various angles, but the results have not varied exactly in
accordance with those angles, because they do not act suc¬
cessively on undisturbed air.

An experiment was tried with 12 planes to each wheel,
the total surface being about 160 feet, when one plane broke
with the pressure. It was cut away and it was worked with
11 planes in one wheel and 12 in the other.

The Hon. Secretary, who had hitherto been a constant
attendant, having been disabled by a collision occurring
on the„ Crystal Palace line, Captain Greenfield, of the Royal
Artillery, one of our Members, very kindly offered to act in his
place. This he continued to do for many weeks, and it is by
his report that we are enabled to confirm the facts here stated.

Mr. Moy had in the aerial steamer an engine of about
three-horse power weighing 801b.

Would it raise 1001b. — that is, would it raise itself and
201b. additional ?

By carefully weighing and balancing it was found that
upon actual experiment the engine was capable of lifting 1201b..

Let us recapitulate the particulars, in order to show how
this calculation is arrived at. The piston is 2|in. diameter,
stroke 3in., revolutions of engine 536 per minute (steam blowing
off all the time) revolutions of aeroplane wheels 67 per minute,
pressure of steam 1401bs. per square inch, cut off at half -stroke,
giving 99,696 foot pounds per minute. This speed gave nearly
one pound per square foot of aeroplane.

AEBOlfAUTlCAI, SOCEETt

It must now be very carefully noticed that although these
aeroplanes were working in a path of disturbed air, yet this
result was arrived at, that 3 indicated horses power lifted one
hundred weight in round numbers ; but suppose this steamer
had been large enough to contain an engineer, and that he could so
manoeuvre as to make it act, in ascending, on undisturbed air,
the pressure would then have been nearer 21bs. per square foot,
and the engine resistance would then have increased in a like
proportion ; but he would at once have altered all the angles
to a much finer pitch ; this would ease the duty again on the
engine and give all the lift required.

Upon a subsequent occasion the experiment was repeated
in presence of the Duke of Argyll, the Duke of Sutherland,
the Earl of Dufferin, Mr. Wright, Mr. Donaldson Hudson,
Oapt. Greenfield, and Mr. F. W. Brearey, who were satisfied
that the experiment, so far as it went, was a complete success.

The members of this Society will read with interest the
forgoing account, and will acknowledge that, although our
progress has been slow, it is promising, and calculated to
awaken the energies of engineers and capitalists.

It was one of the effects of our Exhibition of 1868, that it
drew forth and encouraged the energies of such a man as
Mr. Moy, who, being then an exhibitor, secured the assistance
of Mr. Shill, another exhibitor, for the purpose of working
at this difficult problem, to forward which the Aeronautical
Exhibition was inaugurated.

OF GREAT BRITAIN.

MEMBERS.

Alexander, A., M.A., C.E., Cyclops Steel and Iron Works, Sheffield ;
of the Council

Anderson, Capt. A. Dunlop, 23rd Punjab Pioneers, 21, Lennox Street,
Edinburgh

Arbuthnot, H. Gough, 40, Prince’s Gate, s.w.

Argyll, His Grace the Duke of, F.R.S. ; President of the Council
Armour, Jambs, C.E., Gateshead
Ashbury, James, 66, Grosvenor Square, w.

Ballard, Stephen, C.E., Colwall, Great Malvern
Barber, William, 9, “The Boltons,” Kensington, w.

Baring, Colonel, 36, Wilton Place, s.w.

Barnett, E. W., 25, Lancaster Gate, w.

Barrett, Frederick, Langley House, Grove Lane, Camberwell, R.e.
Baxter, Richard, F.R.G.S., 19, Leinster Gardens, w.

Beadon, Captain R.N., Creechbarrow, Taunton
Bell, Charles W., Roche Court, near Salisbury
Bennett, T. J., 20, Little Clarendon Street, Oxford
Borthwick, Lord, 35, Hertford Street, May Fair
Bourne, John Fred., C.E., Louth, and Civil Service Club
Bourne, Mrs., Hilderstone Hall, Stone, Staffordshire (AnociateJ
Bowles, Thomas G., 88, St. James Street, s.w.

Brbaret, Fred. W., Maidenstone Hill, Blackheath ; of the Council , and
Honorary Secretary

Bright, Sir Charles Tiltson, F.R.A.S., 26, Duke Street, Westminster,
s.w. ; of the Council

Brooke, Charles, M.A., F.R.S,, 16, Fitzroy Spuare ; of the Council
Brooks, Maurice, 10, York Terrace, Regent’s Park
Brown, David Stephens, Bray wick House, Green Lanes, Stoke
Newington

AERONAUTICAL SOCIETY

Browning, John, F.R.A.S., 111, Minories, and 63, Strand ; of the Council
Bronton, N.W., 116, Belsize Park Gardens, N.w.

Burnaby, Captain, Royal Horse Guards ; of the Council
Burrell, Edward, The Hermitage, 7, Melina Place, St. John’s Wood
Burton, Rev. Roger Taylor, M.A., Lexden Villa, near Colchester
Butler, William Fred., C.E., 6, Cannon Row, s.w.

Chaplin, James C., 12, Craven Hill, Hyde Park
Chatto, Andrew, 74, Piccadilly
Childs, Thoma8, Beaufort House, Ham

Clare, Walter F., Engineer, 2, Agnes Cottages, Elm Grove,
Hammersmith

Crestadoro, Dr., Free Libraries, Manchester
Crosland, J. M., Holly Lodge, Thistle Grove, South Kensington
Davies, Charles, 47, Pall Mall
Dawson, G. J. Crosbie, C.E., Rowley Park, Stafford
Decruz, E. , Seetarampore Colleries, Raneegunge, Lower Bengal, India
Delane, John T., 16, Sergeant's Inn, Fleet Street
De Satrustequi, Don Joaquin Marcos, Consul General de Espana,
21, Billiter Street

De Villeneuve, Dr., Rue Lafayette 90, Paris

De Vogt, H. C., 23, Gloucester Place, Hyde Park

Diamond, Hugh W.. M.D., F.S. A., Twickenham House; of the Council

Dufferin, Earl of, 8, Grosvenor Square ; Vice-President of the Council

Ellis, James, 337, Strand, w.c.

Elphinstone, Lord, 24, Carlton House Terrace

Emden, Walter, 76, Russell Square

Ganthony, Richard, Eton Lodge, Richmond

Glaisher, James, F.RS., F.R.A.S., <fcc., Blackheath ; of the Council

Greenfield, Capt. J. Tyndall, R.A., Stanton Harcourt, Upper Norwood

Greetham, Thomas, 26, Bedford Row, w.c.

Grosvenor, Lord Richard, M.P., F.R.G.S., 76, Brook Street, w. ;
Vice-President of the Council

Hall, Alexander Lyons, F.RG.S., 48, Blenheim Crescent, Notting Hill
Hall, George Samuel, Saville House, Billingshurst, near Horsham,
Sussex

OF GREAT BRITAIN.

IT a mm ant, W., 32, Bouverie Street, Fleet Street

Harrison, A. Stewart, 133, Upper Thames Street

Hart®, Richard, 2, Devonshire Terrace, Notting Hill Gate

Hay, Rear-Admiral Lord John, 149, Piccadilly ; of the Council

Hodges, F., Leicester

Holland, Robert, Stanmore, Middlesex

Hudson, C. Donaldson, 51, South Audley Street

Ingall, W. T. F. M., Greenhithe, Kent

Jay, R. C., 54, Alexandra Road, Cambridge Gardens, Kilbum, w.
Jennings, William, F.R.G.S., 13, Victoria Street
Krueger, W. G., Downeville, Sierra County, California
Latham, Baldwin, C.E., 7, Westminster Chambers
Le Fbuvre, Wm, H., C.E., F.R.G.S., St. Antholin’s Chambers,
26, Budge Row, Cannon Street, e. o. ; of the Council
Lilibnthall, Otto, Albrecht St. 13, Berlin
Lindsay, Lord, 47, Brook Street, w.

Londonderry, the Marquis of, Holdenesse House, Park Lane
Longridge, James A, C.E., 3, Westminster Chambers
Ludeke, J. Ernest F., 15, Wilmot Place, n.w.

Macdonald, Colonel, 27, Park Lane, w.

Manners, Lord, Guards’ Club, s.w.

Marriott, Frederick, San Francisco, California
Matthews, Edwin, 26, Bedford Row, w.c.

Maxwell, Captain R. J., Army and Navy Club, s.w.

Michaels, J. Porter, Christinen Gasse, No. 4, Kolowratring, Vienna
Morrieson, Colonel R., Oriental Club
Moy, Thomas, 37, Faringdon Street
Mulliner, F., 59, Great Charlotte Street, Liverpool
Nees, Chistopher, Telegraph Director, Elsinore, Denmark
Newman, Frederick, C.E., 51, Belsize Road
Offenheim, Victor R. Von, Schwarzenberg Strasse 18, Vienna
Ohren, Magnus, A.I.C.E., F.C.S., Lower Sydenham ; of the Council
Osler, Abraham Follett, F.R.S., Birmingham
Owen, Captain R.A., 43, The Common, Woolwich
Pknaud, Alphonse, Archiviste da la Socidt^ Navigation Aerienne,
14, Rue Castellane, Paris

AERONAUTICAL, SOCIETY

Perioal, Henry, Jun., 9, North .Crescent, Bedford Square
Phillips, W. H., Cemetery Road, Nunhead
Procter, J., Old .Castle Buildings, Preeson’s Row, Liverpool
Rislet, J. B., C.E., Brondeg, Ferryside, South Wales
Roberts, Major EL C., 48, Hereford Road, Bayswater
Rowley, James, Engineer, Sunnyside, Gypsy Hill, s.e.

Senecal, P., 95, High Street, Kensington
Shill, Richard E., 37, Farringdon Street

Siemens. C. W., C.E., F.R.S., 3, Great George Street, Westminister
Strinofellow, John, Chard, Somerset

Sutherland, His Grace the Duke of ; Vice-President of the Council
Thorman, A. J., 281, New Cross Road, s.E.

Tolme, J. H., C.E., 9, Victoria Street, Westminster
Tract, The Honourable Henry Hanbury, Gregynog Newtown, Mont¬
gomeryshire

Walker, Charles Clement, Lilleshall Old Hall, Salop
Walker, Thomas, 24, Oxford Street, Birmingham
Wenham, F.H., C.E., V.P.R.M.S., Padnall Hall, Chadwell, Essex ; of
the Council

Wilson. Georoe, 7, Church Terrace, Union Grove, Clapham
Wright, Henry, Stafford House, St. James’ ; of the Council
York*, Pierce Wynne, Dyffryn Aled, Abergele

OF GREAT BRITAIN.

PRESENTED BY THE COMMISSIONERS

THE FOLI/OWING

SPECIFICATIONS OF PATENTS.

No.

Date.
1874.

81 Jan. 7.

Subject.

Patentee.

Improved Apparatus for Naviga- ) Henric Christian
ing the Air . / de Vogt.

777 Mar. 3. Improvements in, and apparatus ) Joseph Douglas
for Aerial Navigation . J Ridley.

1144 Apr. 2.

War and Commercial Aerostatic — 1 Jean Sebastian.
Hot-air Balloons . J Anacharsis Mdnier

2808 Aug. 14.

2821 Aug. 15.

Improvements in Aerial Naviga- j
tion, and in Apparatus for > Thomas Moy.
effecting the same . )

Improvements in the manufacture
of Light Gases, and in the method
of Inflating Balloons therewith
(for Military & other purposes), &
in Machinery and Apparatus for
such purposes, and for Directing,
Guiding, Propelling, and Manag¬
ing such Balloons .

• I sham Baggs.

3132 Sep. 12. Improvements in the Construction 1

of Balloons, and in Apparatus > Joseph Simmons,
applicable thereto . j

3177 Sep. 12. Means and Apparatus for Aerial ) pre(jerjck Hime
Navigation . j

3371 Oct. 2. An improved mode of and Apparatus
for propelling vessels through air
or water .

Henry Whiteside
Cook.

3831 Nov. 6.

Improvements in Balloons and in
the method and Apparatus for
inflating the same .

Alexander Watt.

3996 Nov. 21. Improvements in Navigable Balloons, 1

applicable also as a mechanical f Edwin Powley
and philosophical toy (communi- 1 Alexander,
cated by Stanislas Ludovic Brian) )

Cmtjj Annual ^eporl

or THE

AERONAUTICAL SOCIETY

GREAT BRITAIN.

FOR THE YEAR 1876.

P RUTTED BT

HENRY S. RICHARDSON,

(JREINWICH.

Reprinluced mid printed photolitho offset for
1’ktkk .M I'rray Htli, (Publishers) Ltd.

73 Sloan F. Avenie
London S.W.3
1056

tip permission of the Royal Aeronautical Society

MADE AND PRINTED IN UKEAT BRITAIN BY
D. H. HIM, MAN <fe SONS LTD., FROME

THE

AERONAUTICAL SOCIETY OF GREAT BRITAIN.

- .$• -

President,

HIS GRACE THE DUKE OF ARGYLL, K.T.

Utte=Pre0ftjent0,

HIS GRACE THE DUKE OF SUTHERLAND.
RIGHT HON. THE EARL OF DUFFERIN.

LORD RICHARD GROSVENOR, M.P.

f^anoravg Secretary,

FRED. W. BREAREY, Esq.

I^onoratg Solicitors,

Messrs. MATTHEWS & GREETHAM, 26, Bedford Row.

Council,

A. ALEXANDER, Esq., C.E., M.A., Sheffield.

FRED. W. BREAREY, Esq., Maidenstone Hill, Blackheath.

Sir CHAS. T. BRIGHT, F.R.AS., 26, Duke Street, Westminster.
CHARLES BROOKE, Esq., M.A., F.R.S., 16, Fitzroy Square.
JOHN BROWNING, Esq., F.R.A.S., F.R.M.S., 111, Minories, and
63, Strand.

Captain BURNABY, Royal Horse Guards.

HUGH W. DIAMOND, Esq., M.D., F.S.A., Twickenham.

JAMES GLAISHER, Esq., F.R.S., F.R.A.S., Blackheath.
Rear-Admiral Lord JOHN HAY, C.B., 149, Piccadilly.

W. H. LE FEUVRE, Esq., C.E., F.R.G.S., 28, Brunswick Gardens, w.
MAGNUS OHREN, Esq., A.I.C.E., F.C.S., Lower Sydenham.
Lord LINDSAY, F.R.AS., 47, Brook Street.

F. H. WENHAM, Esq., C.E., Y.P.R.M.S., Padnall Hall, Chadwell,
Essex.

HENRY WRIGHT, Esq., Stafford House, St James’.

with power to add to their number.

Member’s Subscription, £1 .Is. per annum, dating from the day of Election.
Ladies may become Associates upon the same terms.

Ctntjj Annual j£it$oxt

OF THE

AERONAUTICAL SOCIETY OF GREAT BRITAIN,

FOR THE YEAR 1875,

Containing an Account of the Proceedings, and a Selection from the
Papers and Communications received by the Society during the
year, with concluding Remarks upon the present state of the
Science.

The Annual Meeting of this Society was held on
Wednesday, the 23rd June, 1875, at Eight o’clock, in the Rooms
of the Society of Arts, John Street, Adelphi. James Glaisheb,
Esq., F.R.S., presided over a fairly-well attended Meeting.
The audience included several ladies. Particular interest
attached to the present assembly in view of a Paper by
Mr. Moy, on his recent invention of “The Aerial Steamer.”

Mr. F. W. Brearey, the Secretary, began the proceedings
by announcing that Mr. Glaisher would take the chair.

The Chairman, on assuming that position, said : — Ladies
and Gentlemen, it has fallen to my lot on several occasions, as
you are aware, in the absence of the President to occupy this
chair, and on each occasion I have had some points of progress
to indicate in regard to the labours of the past year, and on the
present occasion there is perhaps as much to speak of as in any one
of those years. I have now merely to speak of the intricate and

AERON AUTIC AL SOCIETY

difficult problems which so many good men have been endeavour¬
ing to solve. Two of our own Members, Messrs. Moy and Shill,
have been spending I should be sorry to say how much money,
but, more than that, they have been spending I do not know
how much time ; but I am not ignorant of the very high ability
with which they have devoted themselves from time to time to
the construction of a new steam engine on their own pattern.
They have achieved a degree of success which I could scarcely
have expected last year, and they have now produced a machine
which has lifted vertically a weight of 1201bs. This fact is so
important and so pregnant with our future success that I will
not now longer occupy your time with speaking of it, as we
have Mr. Moy himself here to explain to you what he has done
and what he still expects this engine will be able to do.

Another prominent feature in the past year’s work is the
sad calamity abroad. It was the case of gentlemen devoting
themselves not to the mere pursuit of novelty, but using the
balloon with a view of increasing our knowledge, and in that
pursuit they lost their lives. It was a sad calamity, but I will
not dwell longer upon it now, as I thought you would expect
from me some particulars of the journey which ended so fatally,
and I have been furnished with many facts by my friend,
M. Tissandier, and I shall devote some time this evening to
speaking upon them ; therefore I will not now claim your time
longer, but will ask Mr. Moy to give us, as fully as he thinks
proper, the results he has achieved.

Mr. Moy read a Paper on “Aeronautical Progress.”

After indulging in a diatribe upon the inclination of man
to destroy birds in the name of sport, Mr. Moy read as
follows : —

When I first began seriously to contemplate mechanical
flight, now nearly 30 years ago, I had very little hope of

OF GREAT BRITAIN,

imitating any of the numerous living examples which I saw
continually around. Like a great many more I thought, for
some years, of the “ displacement theory.” A certain amount
of gas of small specific gravity, enclosed in a certain bag of a
certain shape, and propelled by some suitable power, and the
best that man could do would be accomplished. This was my
idea from 1847 to 1859 ; but in this period the steam engine
had made some rapid strides, and engines of something less
than one ton to the horse-power had been made, and I began
to think that steam might after all be made available to propel
aeroplanes, and that Henson and Stringfellow might have
succeeded if they had had more power, with a more effective
imitation of nature.

In 1865 the celebrated “Reign of Law,” by His Grace
the Duke of Argyll, was read by many with an interest which
was entirely due to its merits, and after much thought upon
the subject in that year, I discovered that an inclined plane
might be driven at any reasonable speed, whether fast or slow,
with the same power, provided the front edge was rigid and
sharp, and that the angle was made only sufficient to prevent
falling at the desired speed. From that moment I abandoned
gas.

After much thought and time we had the Exhibition of
this Society, in 1868, at the Crystal Palace, which gave a
fresh impetus to the activity of my mind upon the subject, and
many plans were formed, half matured, and thrown aside for
more hopeful ideas. Amidst all this hard work it was always
kept in mind that the motive-power required remodelling, and
having looked about in vain for a suitable steam engine, I
thought out the steam engine which is well known as the
“Moy and Shill engine,” and in which the great, cumbrous,
separate boiler is entirely done away with.

Having got the motive-power, the next step was to apply

AERONAUTICAL SOCIETY

it ; and here the road was anything but a Royal one. I have
heard Members of this Society urge the necessity of density and
gravitation to the accomplishment of aerial flight ; but I can
assure those Members that there is nothing easier than to
retain density or weight, and that the law of gravitation fully
recognizes every pound of the weight. The great trouble is to
get rid of sufficient density, and so to reduce thereby the effects
of gravitation, that the motive-power will be strong enough to
overcome that amount of gravitation which cannot be got rid
of. To do this it is useless to have recourse to displacement,
as this at once makes the resistance so formidable that speed
becomes impossible.

It would take too much time to trace the successive steps
which have been made. In 1869 I had settled the main
features of the aerial machine, or, as we will in future call it,
the “ aerial steamer.”

Diagrams handed round.

The diagrams, Figures 1, 2, and 4 (now handed about)
show how the revolving and fixed aeroplanes are disposed, with
the engines in the centre of the cabin. One pair of wheels
were to be driven by one engine forward, and the other pair by
the after engine, and the four wheels so geared together that
one engine was at the half-stroke, while the other was at a
dead point, in order to insure continuous motion.

A great deal of time and money was expended in carrying
this out. The novel patterns for this engine were made from
my drawings by my partner, Mr. Shill. The castings were of
gun-metal ; diameter of cylinder 2 inches ; length of stroke
2 inches ; steam at lOOlbs. to the square inch was cut off at
one-eighth of the stroke.

The revolving planes were fitted into hoops made of pine,
6ft. diameter, wire in tension being used instead of spokes, like
the well-known bicycle phantom wheels. The outer planes

OF GREAT BRITAIN.

were so adjusted that as they rose upward in their successive
revolutions they received an upward pressure on their under
surfaces, and for about 200 degrees of the revolution the
pressure was on the reverse side of the planes, and thus the
effective action was without any wasted effort.

Numerous reconstructions took place in the engines, valve-
gear, framing, wheels, &c., until it was thought advisable to
design another engine with greater power. This was commenced
last Autumn, and I think I may say that it has turned out to
be the best engine for its weight that has been yet constructed.

Mr. Moy then proceeded to give particulars of the experi¬
ments which had taken place at the Crystal Palace, but, as they
were embodied in the “Concluding Remarks” of the Annual
Report for 1874, this part of Mr. Moy’s Paper may be omitted.
His Paper continues as follows : —

Every real inventor has to deal with the irrepressible
objector and the self-styled “practical man,” and I may say
that the stupidity exhibited by the objectors to this steam
engine for the last three years is something marvellous. I
need not repeat their objections here. It is simply a steam
engine, and in it steam is raised rapidly, used economically and
effectually, and weight can be reduced to a minimum when
required ; space is also greatly reduced as well as first cost ;
and if those advantages are not sufficient I should like to know
what will satisfy the fastidious requirements of the irrepressi¬
bles. If any one still doubts the merits of this steam engine,
let him produce a 3-horse engine which will lift in air 50 per
cent, more than its own weight ; a 6-horse engine which will
lift in air 100 per cent, more than its own weight ; or a 100
horse-power engine which will lift 40 hundred weights, and
then, if he can do that, I surrender.

Now, having cleared the ground, I come to practical
application.

AERONAUTICAL SOCIETY

I propose to build an engine of 100 horse-power, ascertain
exactly what it will do by dynamometer, then build the aerial
steamer with sufficient surface, cabin accommodation, and
steering apparatus, to make it rise vertically from the ground,
and when clear of the trees, &c., to alter the angles of the
aeroplane wheels and aeroplanes so as to travel in any required
direction.

You will notice in the diagram that the revolving aero¬
plane wheels are perfectly horizontal. This gives a vertical
effect so as to raise it directly from the ground. Having done
this the orbit of the wheels can be altered so as to cause the
impulse to take a diagonal direction, when the steamer will
travel in the direction of the arrow. If higher speed is
required the aeroplane wheels are made to assume a more
vertical orbit, and the pitch of the planes is increased, the fixed
planes coming more and more into action as the speed is
increased ; and when it is required to slacken speed, the angle
of the orbit of the aeroplane wheels is caused to approach
again to the horizontal position, and the speed can be reduced
as desired.

But you will say this is all very fine talking, but what sur¬
faces will you employ, and what materials will you be able to
adopt ? This has all been thought out, and tables made from
data already obtained, which show that, for a really practical
machine, very little else than steel and gun-metal will be
required, so that it will be more of the style of a stag-beetle
than a butterfly.

It is quite as easy to get 501bs. to the square foot of
surface as it is to get one pound ; and when we get 501bs. we
can use metallic surfaces, and the space travelled is passed
through at a much higher speed. The revolving aeroplanes
also to a large machine can be made far more efficient than
those of a model, and comparatively fighter.

OF GREAT BRITAIN.

If any of you were to attempt to model a windmill, on the
scaleof half-an-inch to the foot, with its delicate controlling appa¬
ratus, you would find it simply impossible to keep to scale ; yet the
real working windmill is comparatively very easy to make, and
so it is with the model aerial steamer. Many important parts
are obliged to be entirely omitted in the model which would
be absolutely necessary in the large steamer, and could, on a
large scale, be made comparatively light ; and thus it is that we
can calmly contemplate making a large aerial steamer suitable
to carry passengers with comfort, and to condense all our steam
and use the condensed water again in the boiler, to make the
engines on the compound principle, and the various arrange¬
ments for steering and controlling the steamer all complete and
handy, while in models these must be omitted because they
would be too delicate.

One is met with such singular remarks on this subject
that a few more particulars would not be out of place here.
The body, or, to use a ship-building phrase, the “hull ” of the
aerial steamer will be 70ft. in length, 8ft. beam, and 8ft. in
depth, well trussed to give longitudinal stiffness. This will be
of metal, and a considerable portion of the roof and sides will
be cellular, having about an inch of space between the outer
and inner surfaces. The outer surface will, of course, be in
contact with the air, the inner surface will be in contact with
the air in the cabins. The space between these two surfaces
is a receptacle for the exhaast steam. Every one knows that
when the exhaus* steam is let into this space it cannot con¬
tinue steam ; it must condense, and in doing so it parts with
its latent heat, which is, of course, taken away by these metallic
surfaces. The water trickling down the sides will be passed
again into the steam generator to be again converted into steam,
and thus render unnecessary any great store of water, and the
heat parted with by the condensed steam will warm the cabins.

AERONAUTICAL 80CIETY

There is no reason why the cabins should not be made
comfortable, and at whatever speed the steamer travels the
aeronauts would never be exposed to the current of air. All
the controlling gear will be trained into the cabin, and windows
will be fitted in the sides and bottom of the cabins to enable
the aeronauts to travel by observation. The steering to the
right or left will be effected by means of the driving wheels,
the angles of which can be altered at will, and the amount of
elevation can be effected by the fixed and steering planes.

In illustration of the vertical movement, I have here a
little model belonging to our active and worthy Secretary,
Mr. Brearey, which, by the rotation of four wings in contrary
directions, raises itself. It does not carry up its motive-power,
as the power is exerted in winding up the spring, but it serves
to illustrate the action of the rotating inclined surfaces.

Models are very pretty things to illustrate a Lecture, and,
when well made, are very effective, but they entail an enormous
amount of trouble and delicate manipulation, and the speed of
rotation is necessarily so great, that gyroscopic action takes
place and interferes very greatly with the intended effect ; and
I must confess to a strong feeling of dislike to the finnicking
work. The model at the Crystal Palace is 25ft. wide, and is
quite small enough to my mind, and I should have had great
pleasure in having it here to-night and working it before you ;
but as the wheels are 12ft. in diameter, and of course require
a doorway of that size to admit them, the steamer could not
be brought here.

In concluding a Paper on “Aeronautical Progress” it
would be very unfair to omit to mention the interesting and
thoughtful labours of Mr. Wenham, whose Papers, read before
this Society, and accounts of experiments made by him, have
been of a most interesting and useful character, and whose
steady firmness in the ultimate success of this Society is
beyond all praise.

OF GREAT BRITAIN.

There is a class of objectors to aerial navigation who are
very fond of Time. “Yes, my good fellow, 50 or 100 years
hence it may be done, but not in our time, oh no ! bye-and-bye,
but not now.” These people seem to see a great merit in
distance and reverence delay, and, for the life of me, I cannot
see where the advantage lies. I believe in “work” and in
making use of the present time, and, as I told you in 1868 so
I tell you now, that thought, work, and money can and will
do it.

On the conclusion of the Paper

The Chairman said there was one question of the Paper
which Mr. Moy could make clearer, and that was, whether the
1201bs. weight had been determined by a Salter’s Balance?

Mr. Moy said they found the Salter’s Balance was
interfered with by the motion of the piston. They weighed
the machine carefully and found it weighed 1861bs. They then
put little levers, one on each side, with weights, to take off all
above 1201bs. The machine then rose an inch-and-a-half from
the floor.

The Chairman : Then it was determined by actual experi¬
ment ? because the Paper led us to think it was based upon
calculation only. It is evident that it is an absolute fact that
it did rise this height from the ground.

Mr. Moy : The Duke of Argyll and the other noblemen
and gentlemen present were quite satisfied with it.

Mr. Brown : It does not appear to me whether the engine,
boiler, and framework completely rose. Did the whole machine
go up?

Mr. Moy : The engine with its generator and frame
weighed 80lbs. It lifted 1201bs.

Mr. Brown : I suppose the whole went up ?

Mr. Moy said 801bs. was the weight of the engine, there-

AERONAUTICAL SOCIETY

fore the engine lifted itself and 401bs. besides. Balanced levers
lifted 661bs. of the whole 1861bs.

Mr. Wenham remarked that he had little to say on the
general subject, but as Mr. Moy was flying a light engine he
could give him a little information on the subject. He
(Mr. Wenham) had prepared a condenser. The exhausted
steam was passed into a chamber where 15 cubic feet of air
was sufficient to condense one foot of steam. The condenser
was very light, the walls being made of tin plate. Condensation
was obtained simply by mixing steam with air, in a way that
seemed never to have been practically done before. Mr. Moy,
as a practical man, would see that such a condenser could be
made of the thinnest metal ; tin plate in fact.

Captain Greenfield, B.A. : It may be interesting to
gentlemen here to have the evidence of an outsider on this
matter. In Mr. Brearey’s absence during the spring, when
he was suffering from injuries received in a railway accident, I
officiated for him for a short time as Secretary of the Society,
and on the strength of that basis Messrs. Moy, Shill, and
Childs very kindly invited me to these experiments on Monday
last before the Duke of Argyll, the Duke of Sutherland, the
Earl of Dufferin, and several others. I took notes of what I
observed, and recorded the revolutions and the amount of work
done. I should first describe how the engine was arranged.
It rested on the floor on its base. The engine was resting on
a very narrow base against the framework of the machine, and
the two ends, that is to say the spindles of the wing wheels,
were supported by little levers, the arms of which were of
equal length, and each one was weighted to about 331bs. on
each side, making 661bs. on both. 661bs. weight was thus
taken off the engine by those little levers. The work to be
done was to raise — no matter whether one inch, one foot, or one
mile — the work was to raise the whole engine, then weighing

OF GREAT BRITAIN.

1201b8. One of the wing-planes having been broken previously
to the experiment there remained on the one side only eleven
wing-planes against twelve on the other side, consequently the
wing on one side was unable to do its work completely ; there¬
fore I found the complete and perfect wing rose much more
than did the imperfect one. The complete one rose on one
occasion six inches, lifting the whole body of the apparatus a
distance of two inches from the ground ; therefore the work
done was that 1201bs. was lifted by the apparatus within itself
two inches from the ground at the very least. On the other
side it was lifted six inches.

The Chairman : Vertically ?

Captain Greenfield : Vertically. This was done with the
assistance of 661bs. at the extremities, without any other power
than the revolution of the wings in the air ; but that was in
still air, not in moving air. There was no draught at the time
the machine was in motion. I have reason, from what I saw
then, to believe that, by a slight re-adjustment, the engines
ought to be able to do more than that. In a space of 94-5
seconds I made a calculation of 99000 odd pounds of pressure.

Mr. Moy : Foot-pounds ?

Captain Greenfield : Foot pounds of course. The wings
being unequal in operating there was a good deal of oscillating
motion. One wing was unable to rise as much as the other,
but at last, as I say, one wing rose six inches and the other rose
two inches, giving a mean of three or four inches. (Applause.)

The Chairman : I am sorry I was unable to be present
last week to see those experiments. I now rise to ask you to
give a vote of thanks to Mr. Moy for his Paper. As I observed
in my opening remarks Mr. Moy has spared neither time nor
money, but the results have been what you have heard. The
remarks by Capt. Gbeenfeeld on these experiments are exceed¬
ingly valuable. I have now to ask you to give your heartiest

AERONAUTICAL SOCIETY

thanks to Mr. Moy and your best wishes for the future. May
his hopes be realized in further experiments.

The thanks of the Meeting were accorded to Mr. Moy.

The Chairman then read the following Paper, contributed
by himself, on the

DEATH of CROCfi-SPINELLI and SIVEL.

On the morning of Thursday, 15th of April, 1875, at
11.35, the balloon, Zenith, left the Gas Works of La Villette,
with Messrs. Tissandier, Croo^-Spinelli, and Siyel in the
car. Three small balloons, filled with a mixture of air and
oxygen in the proportion of 70 to 100, were fastened to the
hoop. From the lower part of each depended a tube of
caoutchouc, which passed through a wash-bottle filled with an
aromatic liquid. This apparatus was intended to supply the
voyagers, when in the upper regions of the atmosphere, with
the necessary amount of oxygen for maintaining life. An
aspirator, filled with essence of petroleum, which would not
solidify owing to the fall of temperature, was suspended outside
the car. It was to be set up vertically at the height of about
10,000ft., for the purpose of injecting air into the tubes of
potassium intended for the determination of the carbonic acid.

Sivel had fixed wdthin reach of his hand some bags of
ballast, which would empty of themselves on cutting the string
which held them. He had fixed underneath the car a thick
mattress of straw to deaden the shock of descent. Oroce-Spinelli
had brought with him his spectroscope, so frequently employed
in the preceding voyage of the Zenith. From the ropes of the
car were suspended two Aneroid barometers, which had been
verified, previously to starting, under the air-pump, the first
giving readings corresponding to heights from 0 to 13,000ft.,
the second readings from 13,000 to 29,500ft. Near to these
instruments was suspended a thermometer of red alcohol for

OF OBEAT BBXTAIK.

for the measures of the lowest temperatures, graduated down
to 22° Fahrenheit, and a minimum and maximum thermometer
which, by means of an endless cord fastened to the valve, could
be introduced into the interior of the balloon, for the purpose of
determining the temperature of the gas ; also, in a sealed box
and carefully packed in sawdust, were eight barometric test-
tubes, intended to furnish, after the descent- of the balloon, an
exact record of the greatest height attained. Charts, compasses,
and printed question-papers, to be dropped from the car,
completed the scientific materiel of the expedition.

The balloon ascended at the rate of 6 or 7ft. per second,
decreasing gradually till it reached 11,500ft., after which it
rose rapidly to 16,500ft., under the action of a brilliant sun
and by the discharge of ballast. Sivel during this time was
occupied with the anchor-rope, and in taking precautions for
landing. Scarcely had 1,000ft. been reached when he joyfully
exclaimed, “We are well on our way, my friends. I am very
well pleased.” A short time after, gazing at the swelling
balloon above the car, he said, “ Look at the Zenith, how well
filled she is, how well she looks.”

Croce-Spinelli said, “Now Tissandier : now for the aspirator
and the carbonic acid ! ” and M. Tissandier prepared his apparatus
for injecting 70 litres of air into the tubes of potassium at a
height of from 13,000ft. to 20,000ft.; but these tubes, which
he had not strength at the last moment to secure in the padded
box, must in the descent have been broken.

At the height of 10,500ft. gas escaped with force from the
open neck of the balloon. The odour was perceptible, but
neither Sivel nor Tissandier felt inconvenience from it, but it
is important to notice the following lines which were found
written in the note-book of Croce-Spinelli: — “llh. 57m.;
barometer nearly l^Sin. ; temperature + 2°. Slight pain
in the ears. A little oppressed. It is the gas.”

A EBON ATJTIGAIi SOCIETY

It should be stated that the Zenith was not fully inflated,
so that a large space was left for dilatation.

At 13,000ft. the sun was hot, the sky resplendent, and
with numerous cirrus clouds extending to the horizon.

At 14,000ft. they began to breathe oxygen, not because
there was any necessity for its use, but only to convince them¬
selves that the apparatus was in working order.

At the height of 23,000ft., at lh. 20m., Sivel inhaled the
mixture of air and oxygen. He was suffering from oppression,
and this cordial invigorated him. At this height he wrote in
his note-book, “ I am breathing oxygen. The effect is
excellent.”

At the same height Sivel, who possessed great physical
strength and a sanguine temperament became drowsy and
slightly pale. He would not, however, suffer himself to be
overcome. Drawing himself up with an expression of firmness
he made Tissandier empty the liquid contained in the aspirator
after the experiment, and in. order to ascend higher he threw
out ballast. Sivel, the year before, had ascended to the height
of 23,000ft. with Croce-Spinelli. He wished this year to
ascend to 30,000ft.

Croce-Spinelli had for some time been occupied with the
spectroscope. He was in excellent spirits, and had just
exclaimed, “ There is a complete absence of the lines of the
vapour of water.” Having uttered these words he had applied
himself to the resumption of observations with so much vigour
that he asked M. Tissandier to write in his note-book the
results of the readings of the barometer and thermometer.

In the course of the rapid ascent, in the midst of so many
occupations, it had been difficult to find time for physiological
observations. These it was intended to make in the higher
regions of the air, and the aeronauts were reserving for them
all their strength, never suspecting the fatal denouement which

OH* OEEAT BRITAIN.

was about to stay their efforts. The following physiological

observations were, however, made : —

Time. Altitude,
h. m. feet.

12.48 ... 10,157 ... Tissandier...llO pulsations in a minute.

1.3 ... 10,767 ... Croce . 120

1.5 ... 10,767 ... Sivel . 155

During the ascent up to 23,000ft. meteorological observa¬
tions were taken regularly. They indicated a gradual diminution
of temperature up to 10,000ft. an increase from 10,500ft. to
12,100ft., and, lastly, a gradual diminution from 13,300ft. up
to 23,000ft., and above.

Table giving the complete results of the Readings.

Time.

Altitude.

Temperature.

h. m.

feet.

11.30

57-2

...

1,194

51-8

...

2,598

46 ‘4

11.40

4,157

46-4

• • •

6,562

44-6

...

10,499

33-8

...

11,482

S4-7

12.15

12,132

35-6

...

13,451

320

• . •

14,393

32-0

...

15,098

32-0

12.51

15,419

32-0

...

17,092

26-6

...

17,092

230

...

17,388

23-0

1.5

18,372

23-0

...

19,029

23-0

...

21,981

17-6

1.20

22,965

14-0

24,227

12-2

• ••

26,246

... unknown

the first time

the interior temperature of a balloon

AERONAUTICAL SOCIETY

has been determined, and the results which have been obtained
are of much interest. Sivel had excellently arranged the cord
for introducing the thermometer into the interior of the balloon,
and Croce-Spinelli twice made the experiment by means of
the apparatus.

The. temperature indicated by the thermometer was 66°
in the centre, and 72° near the valve, whilst floating at the
height of from 15,000ft. to 16,500ft., while the temperature of
the surrounding air was 32°. At 17,500ft. the interior
temperature of the balloon in the centre was 63°, whilst the
external air was 23°. At the time of the catastrophe the
thermometer was inside the balloon, and it was found there
uninjured after the descent. It had risen to the temperature
of 73°.

I now proceed to give in M. Tissandier’s own words his
account of the fatal result of the voyage.

“At 23,000ft. we were standing up in the car. Sivel, who
had given up for a moment is re-invigorated ; Croce-Spinelli is
motionless in front of me. ‘ How beautiful is the cirrus ’ he
remarks, and indeed it was a sublime spectacle which was
offered to our sight — cirrus clouds of different forms, some
long and others slightly rounded, formed around us a circle
of silvery white.

“ I felt stupefied and frozen. I wished to put on my fur
gloves, but, without being conscious of it, the action of taking
them from my pocket necessitated an effort that I could no
longer make.

“At the height of 23,000ft. I made entries in my note¬
book mechanically. I copy, verbatim, the following lines
which were written by me, although I have no very distinct
remembrance of doing so. They are traced in a hardly legible
manner by a hand trembling with cold : —

“ ‘ My hands are frozen. I am all right. We are all all right.

OF GREAT BRITAIN.

Fog in the horizon, with little rounded cirrus. We are
ascending. Croce pants. He inhales oxygen. Sivel closes his
eyes ; Croce also closes his eyes. I empty the aspirator.
Temperature 14° Fahrenheit at lh. 20m. ; barometer reading
12’6in. Sivel is drowsy at lh. 25m. ; temperature 12*2° ;
barometer reading ll‘8in. Sivel throws out ballast.’ These
last words are hardly readable.

“ Sivel, indeed, who had remained for some time pensive
and immovable, at times closing his eyes, had just remembered,
doubtless, that he wished to ascend beyond the present height.
He rouses himself and turns towards me and asks, ‘ What is the
pressure’? I reply, ‘ll*8in.’ ‘We have plenty of ballast,
shall we throw some out ? ’ he asks. I reply, ‘ do as you like.’
He turns towards Croce and asks him the same question.
Crose makes with his head an energetie sign in the affirmative.

“ In the car were at least five bags of ballast ; nearly as
many were suspended by fine cords outside. These, I ought to
add, were not quite filled. Sivel certainly could have stated
their weight, but I can give no estimate myself.

“ Sivel seized his knife and cut successively three cords,
and the three bags emptied themselves and we ascended rapidly.
The last remembrance of this ascent which remains clear to me
relates to a moment earlier. Croce-Spinelli was seated, holding
in one hand the wash-bottle of oxygen gas. His head was
slightly inclined, and he seemed oppressed. I had still strength
to tap the Aneroid barometer to facilitate the movement of
the needle. Sivel had just raised his hand towards the sky, as
if pointing to the upper regions of the atmosphere. As for
myself I remained perfectly still, without suspecting that I had
perhaps already lost the power of moving. About the height
of 25,000ft. the condition of stupefaction which ensues is
extraordinary. The mind and body weaken by degrees and
imperceptibly, without consciousness of it. No suffering is

AERONAUTICAL SOCIETY

experienced ; on the contrary, an inner joy is felt like an
irradiation from the surrounding flood of light. One becomes
indifferent. One thinks no more of the perilous position or of
danger. One ascends and is happy to ascend. The vertigo of
the upper regions is not an idle word, but, so far as I can
judge from my personal impressions, vertigo appears at the
last moment; it immediately precedes annihilation, sudden,
unexpected, and irresistible.

“ When Sivel cut away the bags of ballast at the height
of about 24,000ft., that is to say under a pressure of ll*8in.,
which is the last number written in my book, I seem to
remember that he was sitting at the bottom of the car and
nearly in the same position as Croce-Spinelli. For my part I
was in the angle of the car, thanks to which support I was
able to hold up, but I soon felt- too weak even to turn my head
to look at my companions.

“ Soon I wished to take hold of the tube of oxygen,
but it was impossible to raise my arm ; my mind, never¬
theless, was quite clear.

“I still kept a watch on the barometer. My eyes were
fixed upon the needle, which soon arrived at the figure indicating
a pressure of ll'4in., then it passed to llin., and even further.

“ I wished to exclaim, ‘We are 8000 metres high,’ but
my tongue was as it were paralyzed. All at once I closed my
eyes, and sinking down inert became insensible. This was
about lh. 30m.

“At 2h. 8m. I awoke for a moment and found the balloon
rapidly descending. I was able to cut away a bag of ballast to
check the speed and write in my note-book the following lines,
which I copy : —

“‘We are descending. Temperature 3° (Fahrenheit). I
throw out ballast. Barometer 12'4in. We are descending.

OF GREAT BRITAIN.

Sivel and Croce still in a fainting state at the bottom of the
car. Descending very rapidly.’

“ Hardly had I written these lines when a kind of trembling
seized me, and I fell back weakened again. There was a violent
wind from below upward, denoting a very rapid descent. Some
minutes after I felt myself shaken by the arm, and I recognised
Croce, who had revived. ‘Throw out ballast,’ he said to me :
‘ We are descending ; ’ but I could hardly open my eyes, and
did not see whether Sivel was awake.

“ I call to mind that Croce umastened the aspirator, which
he threw overboard, and then he threw out ballast, rugs, <fcc.

“All this is an extremely confused remembrance, quickly
extinguished, for again I fell back inert, more completely than
before, and it seemed to me that I was dying.

“ What happened ? It is certain that the balloon, relieved
of a great weight of ballast, at once ascended to the higher
regions.

“About 3h. 30m. I opened my eyes again. I felt dread¬
fully giddy and oppressed, but gradually came to myself. The
balloon was descending with frightful speed and making great
oscillations. I crept along on my knees, and I pulled Sivel and
Croce by the arm. ‘ Sivel ! Croce 1 ’ I exclaimed, ‘ Wake up 1 ’
My two companions were huddled up motionless in the car,
covered by their cloaks. I collected all my strtngth and
endeavoured to raise them up. Sivel’s face was black, his eyes
dull, and his mouth was open and full of blood. Croce’s eyes
were half-closed and his mouth was bloody.

“To relate what happened afterwards is quite impossible.
I felt a frightful wind. We were still 9,700ft. high. There
remained in the car two bags of ballast, which I threw out. I
was drawing near the earth. I looked for my knife to cut the
small rope which held the anchor, but could not find it. I was

AEBOKAUTIOAL SOCIETY

like a madman and continued to call ‘ Sivel ! Sivel 1 ' By good
fortune I was able to put my band upon my knife and detach
the anchor at the right moment. The shock on coming to the
ground was dreadful. The balloon seemed as if it were being
flattened. I thought it was going to remain where it had
fallen, but the wind was high and it was dragged across fields,
the anchor not catching. The bodies of my unfortunate friends
were shaken about in the car, and I thought every moment they
would be jerked out. At length, however, I seized the valve¬
line, and the gas soon escaped from the balloon, which lodged
against a tree. It was then four o’clock.

“ On stepping out I was seized with a feverish attack, and
sunk down and thought for a moment that I was going to join
my friends in the next world : but I came to. I found the
bodies of my friends cold and stiff. I had them put under
shelter in an adjacent barn.

“ The descent of the Zenith took place in the plains near
Ciron (Indre), 155 miles from Paris, as the crow flies. According
to the question-papers dropped from the car, and sent to the
Office of the French Society of Aerial Navigation by those who
picked them up, I feel certain that the Zenith did not deviate
from a straight course, that the wind blew in a straight line,
and that its direction was constant up to a height of 8,000 metres.
The velocity of the air certainly was greater in the upper regions
of the atmosphere than on the ground.

“ The question-papers did not take less than half-an-hour
to descend from the height of 7,000 metres to the ground. A
paper dropped mechanically by me at 3h. 30m., at the moment
of my second awakening, and spotted with blood from a slight
cut which I gave my hand before fainting for the first time, was
caught whilst floating in the atmosphere, 35 minutes after the
balloon came down.

“ Having given the history of the ascent, I come to the

or GBEAtf BBITAIK.

two important questions which have so much engaged the
attention of the scientific world and the public, viz. : — ‘ The
maximum height attained by the Zenith, and the cause of the
death of Croce-Spinelli and Sivel.’

“ A reply to the first question has since been given by the
opening of the barometric tubes, invented by M. Janssen, and
which had been previously employed by Sivel and Croce-Spinelli
in their ascent to 7,300 metres on 22nd March, 1874.

The tubes taken up in the Zenith were examined in the
Physical Laboratory of the Sorbonne, by the assistance of
MM. Berthelot, Jamin, and Herve Mangon. The tubes were
placed under the air-pump, together with a barometer, the air
being exhausted so as gradually to drive the column of mercury
into the curved extremity of the tubes to the position it oc¬
cupied when we attained the greatest elevation. One tube had
been broken, several had been injured or had worked badly,
but there were two, the march of which had been regular.
These furnished concordant results and indicated that the
least pressure was from 104in. to 10*3in., which indicates a
maximum height of from 28,000ft. to 28,200ft.

“ It appears to me certain that the death of my unhappy
friends was caused by the rarefaction of the atmosphere. It
is possible to support, for a short time, the effects of this rare¬
faction, but it is difficult to submit to its continued action for
nearly two consecutive hours. Our sojourn in the upper regions
was continued longer than in any preceding high ascent. I may
also add that the particular dry air might have contributed to
exercise a fatal influence.

“ It will be asked to what cause I owe my safety. I owe
my life probably to my individual temperament, essentially
lymphatic, perhaps to my complete swoon having caused a
kind of arrest of the respiratory functions. I was fasting at
the moment of departure, a circumstance which I at first

AERONAUTICAL SOCIETY

thought peculiar to myself, but I have since had proof that,
whether Sivel had eaten or not, Croce had, like myself, scarcely
any food in the stomach.

“With one exception the few preceding high ascents are
far removed from this altitude. Gay Lussac, in 1804, attained
7,004 metres; Robertson, in 1803, 7,400 metres; Barral and
Bixio, in 1852, 7,016 metres; Welsh, the same year, 6,990
metres. All these voyages, it will be seen, have been limited
to heights between 7,000 and 7,400 metres, which I believe
should be considered as the limits of the respirable atmosphere.

“Our friend and master, Mr. Glaisher, in 1862, ascended
to the height of 8,838 metres. He then suddenly became
insensible and nearly lost his life, and, he has since said, sup¬
posed himself about to die. The height which he believed
himself to have further attained, 11,000 metres, appears to be
very doubtful, as it is only determined by an algebraic proportion
deduced from the speed of the balloon in its ascent and descent.
This savant assumes these velocities to have been constant
during the time of his unconsciousness, whilst they may have
varied and the speed of the ascent have become nil. I may add
that Mr. Glaisher had made similar expeditions, that he had
trained himself little by little, and that it is certain that his
organization had become accustomed to the influence of the
rarefaction of the air, which had endued him with peculiar
faculties for the performance of these voyages.

“ I am persuaded that Croce-Spinelli and Sivel would be
still living, notwithstanding their long stay in the upper regions,
if they had been able to breath oxygen. Like myself, no doubt
they suddenly lost the power of moving, and the abduction-
tubes escaped from their paralyzed hands.”

M. Tissandier adds that he learns, from information
afforded by the Mayor of Courmenin, that the aspirator fell
close to a woman sitting on the grass with her two children.

or OfiEAT BRITAIN.

the noise produced by the shock being very considerable. A
rug and a padded box, intended for the potassium tubes, were
also found near.

After the reading of the Paper

The Cp airman said— A few remarks may justly be expected
from me. It seems to me most strange that three gentlemen,
of different ages and different physique, should simultaneously
become exhausted. I have been at the height at which this
occurred several times and never felt any inconvenience. The
question then arises — Why did these gentlemen die ? What was
the cause of their death ? When I was about six miles high I was
insensible for want of oxygen, but when we came down I
recovered again. No blood could have entered into their
mouths if they had died from rarefaction of the air. It is the
occurrence of the blood which seems to me to present so much
difficulty. I cannot but think that, through indiscreetly
throwing out a great weight of ballast, the balloon must
have ascended like an arrow from a bow. The balloon would
then either burst or the gas escape, and it might have been
that they were seated within the influence of the escaping gas,
and this caused the blood to come. However I cannot satisfy my¬
self as to what was the cause of death. I am sure we shall all
feel admiration for those gentlemen who, from no light motive,
made this ascent to increase human knowledge. With respect
to the remark of M. Tissandier, that the extreme height of
11,000 metres was obtained by an algebraic proportion.
I would add that two other independent determinations
led to the same result. I never had any feeling of
joy at great heights : it was one of intense agony at
five or six miles ; beyond that the death is painless. I
had no pain after we were six miles high. Though the death
itself is painless, nature seems, at certain heights, to gay “ go

AERONAUTICAL SOCIETY

back, you are dying.” I had none of that ecstatic feeling
experienced by the French gentlemen. I am quite ignorant of
it. Directly we approached four miles from the earth I felt
pain. I am sure I may now say that this Society feels very
keenly the loss of those two gentlemen who expired in the
pursuit of science. A subscription has, I believe, been made
for their widows and families.

Captain Burnaby gave some notes of experiments at the
Crystal Palace. These, he said, had reference to an instrument
he had invented some time previously for the purpose of
ascertaining the direction the balloon was going when
floating in a space above the clouds, and more particularly at
night. As many gentlemen present knew, he had made ascents
at night when it was almost impossible to get a line. The
compass indicated East, West, North, and South, but the earth
was hid from their view, the clouds were going the same way
as they were, and, for anything they knew, they might be going
towards France or Germany. He had, therefore, thought of
employing two small parachutes to indicate the direction in
which the balloon was travelling. The parachutes could be
made of silk. They would have magnesium wire in their cars,
and must be attached the one to the other by a long silken
thread. This, in its turn, is fastened to a reel in the car of
the balloon. On dropping one parachute it would at first fall
on the motion of the balloon, but the attraction of the earth
would gradually make the parachute descend. In a few seconds
he would let fall a second parachute. This would act in a
similar manner ; and then, by drawing an imaginary line in
the mind’s eye from the first to the second parachute, the
aeronaut could discover the direction in which he Was travelling.
This he believed, was most important with respect to warfare, and
particularly in respect of postal balloons sent out of a fortress
at night ; otherwise they would not know whether they were

OF GREAT BAIT AIK.

going into the country of the enemy or that of friends. By
this invention they would be able to ascertain the course of the
balloon, and to know whether they should descend or continue
their course. This was a subject which he believed had never
been worked, and he had thought it of sufficient importance
to bring it before the Society.

Mr. Wenham asked whether the parachutes could be
drawn up again.

Captain Burnaby : Yes ; that is the advantage, because
you have a silk cord connecting the two parachutes and con¬
nected with the car by a reel, so that you cannot lose the
parachutes.

The Chairman said whenever he had been above the
clouds and lost sight of the earth he could always determine
the direction of motion by means of the hanging grapnel
rope. If the balloon was standing still the grapnel was
vertical, if moving at all it was out of the vertical, and by
looking at the compass he always knew in which direction he was
moving. That was by daylight ; but in night ascents he had
still seen the rope. Captain Burnaby, who had been with
him, must have remarked that the rope could be seen at night.

Captain Burnaby said they might be able to see it, but
he had known cases when he could not see his hand before
him. It had been bo dark that he could see nothing. He had
had the opportunity of talking on this subject with several of
the men who went up from Paris during the siege.

The Chairman : They were sailors and inexperienced men,
with the exception of M. De Fonveille and two or three others.

Captain Burnaby thought this did not meet the case.
The balloon ascents were mostly made by day because there
were no means of knowing the direction at night.

Mr. Wenham said he could not exactly see on what
principle an anchor, suspended from a balloon, should deviate

aeronautical society

from the perpendicular. Captain Burnaby’s parachutes, if left
at rest, would, after a time, partake of the motion of the car ;
but while the parachute was being quickly raised or lowered it
would have a tendency to fall perpendicularly, and the balloon
at the time traversing in a direction away from the line of
gravitation taken by the parachute, a sensible inclination of the
suspending cord would indicate the direction in which the
balloon was travelling.

The Chairman remarked that the grapnel always followed
the balloon.

Captain Burnaby : At times you cannot see the anchor
at all.

The Chairman : I have been in the car of a balloon when
we could not see the balloon itself.

Captain Burnaby : That is what I make a great point
of. That is the time when it is impossible for the aeronaut
to know the direction in which he is going, but this invention
of mine will enable him to do so.

The Chairman observed that Captain Burnaby spoke
from practical knowledge, and that the Meeting was much
obliged to him for giving the result of his experience.

A vote of thanks was given to Captain Burnaby.

M. Menieb read a Paper, in French, on Experiments
in Guiding Balloons. Several model balloons, inflated and
furnished with the steering apparatus, attached to the balloon
in the form of small sails, were exhibited in the room.

M. Menier said the system of aerial navigation he pro¬
posed was based upon the employment of hot air with accessory
surfaces placed on each side of the balloon. A hot-air
balloon was tried at Woolwich for military purposes. It
was true the balloon had met with an accident, but it was also
quite certain that, on the 16th October, it did rise and lifted a
weight of l,7001bs. With some change in the balloon it was
his opinion it would answer for military purposes. It was this

OF GREAT BRITAIN.

system of the hot-air balloon that had given him the idea of a
plan of aerial navigation and of propelling and steering balloons.
He was not quite sure he understood Mr. Moy, but if his
object was simply to support one man in the air by means of
machinery, he was afraid that was not the intention of aerial
navigation. Aerial navigation, to be useful, must be able to
take the produce of a place from that place to the place
of consumption. The balloon itself seems to offer that
facility, and it was for that reason he had endeavoured
to steer the balloon ; but what were the means of steering it ?
The first was the power of ascent and descent communicated
to the balloon. The second was the resistance offered by the
air to any surface passing through it with speed. One presented
the difference of velocity and the second the difference of
atmosphere. If we employed the power of ascending and
descending, and the resistance of atmosphere, we might probably
be able to steer the balloon. He commended his two inventions
to this Society, and should be glad if they could give him some
support.

Mr. Mov said this plan of driving balloons was an old
acquaintance of his ; it was in an old number of the Mechanics’
Magazine.

M. Menier exhibited two balloons fitted with steering
apparatus and one without. The one unfitted with sails
ascended vertically. One of the others with sails set took a
direction to the right, the other to the left. The experiment
was therefore, in a limited space and an undisturbed atmosphere,
successful.*

Mr. Moy said he had seen a Mechanics’ Magazine of 1824,

* A Model upon this principle was shown by Mr. Heath at the
Aeronautical Society’s Exhibition at the Crystal Palace, in 1868. It
was thus described in the Catalogue — “ Model of a Balloon with a ring
or belt attached, which, in ascent or descent, is placed in an inclined
position relative to the axis of the Balloon . ...” (Ed.)

AERONAUTICAL BOCIETY

in which the same idea was described. If they threw out
ballast to get ascensive power, and let out gas to get descensive
power, they would require so much of both that they would
find the process a most expensive one. A small amount of
steam would drive a screw with greater power.

Mr. Wenham expressed his belief that Sir George Cayley
was the original inventor of this plan.

Captain Burnaby asked if this machine could go against
a wind blowing at fifteen miles an hour. In that room, where
there was no draught, these fans made but a very slight
deflection from the regular course. If there was so small a
deviation now what would there be with the wind at fifteen
miles an hour ?

M. Menier said he made no pretensions at a first trial to go
against the wind. He supposed the propelling and steering of
the balloon must commence at one point and go on at another
time to another. All he now professed to show was that
it might be possible to do that which had, as yet, been done by
nobody. It was not his purpose to show that this balloon
could go against the wind, but he supposed learned men, as
the Members of that Society were, would think it something if
he showed them the balloon, without requiring it to go against
the wind. They might calculate from the ascent, descent, and
resistance what power could be given to the balloon.

Mr. Moy : You would save time if you would give figures.

M. Menier said he was not prepared to give figures.
When it was said he should be obliged to throw out ballast
and lose gas, he must explain that he only used gas for the
purpose of experiment, and that he intended his apparatus to
be applied to the hot-air balloon only.

Captain Burnaby expressed his disapproval of the hot-air
balloon on the ground of the difficulty of inflation and the
danger on touching the ground. The danger of the balloon

OF GREAT BRITAIN.

catching fire was also to be considered. For military purposes
the difficulty of inflating the hot-air balloon made it practically
useless.

The Chairman could hardly believe the balloon could be
guificd in a strong wind, but he was sure, at the same time,
they would all heartily give M. Menier their thanks.

A vote of thanks was given to M. Menier.

The Chairman, in adjourning the Meeting, expressed an
earnest hope that when they met again Mr. Moy would have
taken another step in the direction in which he had commenced.

On the motion of Captain Burnaby the thanks of the
Meeting were given to the Chairman, and the Meeting
separated.

The following Paper, though not read before the
Society, is inserted as being a popularized exponent
of ideas upon the subject of aeronautics, and because
the views put forth therein agree with the experiments
and theories of several well-known Members of the
Aeronautical Society.

AERONAUTICAL SOCIETY

ANGUS AND MACK ON THE AIR PATH.

Two friends, Angus and Mack by name, were sitting
together one evening lately by the fireside, and their talk
was of those in the Alert and the Discovery, who would then
be taking their lonely winter stations apart among the ice, far
north of even the usual summer tracks of man.

In all the region there, there would soon be only one
warm spot, carefully enclosed ; only one spot where there
would be fight, and that fight never but making dark shadows
on the wall ; and with room outside for many a gale between
there and the remote point southward where daylight, like a
tide that had ebbed, would so long be fingering. And over
the trackless waste intervening, riven, and wind swept, and
drifted, what manner of messenger could bring word home to
tell how it was with them when the long night was closing in.

There seemed only the air path ; but as the friends were
not of one mind regarding its availability for man, and
began *o argue : and, as the inertia of doubt in the one was
needed to discover the force of experimental belief in the
other, we shall let each speak for himself, in his own way.

Angus. — A fleein machine do ye say ? that’ll never be.

Mack. — What for no ? I’m sure ye’ve only to look out
o’ doors to see no ane only, but whole flocks o’ them ; ye
need’na gang farther than the sparrow for an instance.

Angus. — Aye, aye, but ye’re no a sparrow.

Mack. — I ken that, but that’s nae argument.

Angus. — Aweel then, we’ll try an mak it ane ; bulk for

OF GREAT BRITAIN.

bulk we’ll grant that the sparrow an you are equal in weight,
but wi’ you, a good deal o’ your bulk is made up o’ legs, show¬
ing cleariy where nature has designed much o’ your strength
should lie : whereas she has gathered the beef o’ the sparrow
about its shouthers tae work the wings, leaving it wi’ scarcely
ony legs at a’.

MACK. — Let the beef bulk where it may, the head will
mak a’ the difference.

Angus. — Ay, but no ony o’ the difference between rinnin
and fleein : though the head may sometimes feel light enough
for fleein if it wer’na for the weight o’ the body.

Maok. — I’m sure ye might jist as weel say it has made
nane o’ the difference between rinnin and ridin in a railway-
train.

Angus. — -Noo Mack, be reasonable; jist waff your hand
to and fro this way, an tell me if ye feel ony thing like what ye
could rin your railway-train on.

Mack. — Hoots man, your hand is ower numb to feel
onything that would stop short o’ hurting. The sparrow
waffs his hands tae mair purpose than you can dae.

Angus. — I dinna see hoo granting that can help ye much.
You y Or sell would flee left-habded ye kett.

Mack. — Its no the hands but the head that’s in
question. When a’ things are ready, the hands maun hae
naethiiig to dae but turn a handle, or open a bit tap noo and
again.

Angus. — What’s the handle to dae ? and what’s to come
oot o’ the taps? win?

Mack. — Maybe ay, and maybe yes. I expect there will
be nae want o’ win’ about them, onyway.

Angus. — Jokin apart though, if there’s to be so little for
ye to dae when ye’re up fleein, what do ye mean should dae
the wark o’ lifting ye and driving ye? for ye’ll be nae mair

AEBONAUTIOAL SOCIETY

able to get quit o’ your gravity when rising in the air than
when gaun up stairs.

Mack. — We’ll speak o’ the driving power when we ken
better what power ’s required : mair than likely it’ll be maist
needed at the start ; in which case, a store o’ ready prepared
force might do much ; and some birds appear to exert them¬
selves sae little once they are up, it’s not unreasonable to hope
that we may learn a way to tak it easy too. Ae thing at least
is dear, we shall have naething but physical forces to deal
with, and there’s surely mathematics among us sufficient to
find out a’ that’s wanted.

Avans. — Ay ; and if mathematics happen to get a haud
o’ the wrang end o’ the string, they can jist talk as much non¬
sense as onybody. I dinna think ye’re ready for them yet,
and ye’ll hae a gude deal o’ open air wark before ye can gie
them the fundamentals to operate on, and while they’re opera¬
ting then, ye’ll maybe be fleein, and they’ll finish in time to
tell ye whether the principles ye’re fleein on are fleein anes or no.

Mack. — I wish I was in the way o’ ^>ving them a chance.

Angus. — Can ye no try figures for yoursell?

Mack. — Do ye want to gie me a sair head?

Angus. — Not for the world ; get somebody wi’ a harder
head than your ain to risk the sairness, for I doubt without
figures ye’ll get badly on ; and I doubt the birds’ll no ' help
ye much, else man would hae got the cue frae them lang
syne.

Mack. — Oh ; but man lang syne did’na ken sae much as
we ken noo. Why, hoo lang was man in the habit of bilin
water before he could see mair in the steam than that, when
the pot lid was tight the hot water cam belchin frae the spout,
and when the spout was at last cut off, and the pot became a
close biler, Papin biled banes in’t to make jelly ; and to have
hinted then about puttin the biler on to wheels, and rinnin ’t

OF GREAT BRITAIN.

on rails at railway speed would have appeared as like delirium
as to some noo appears this talk o’ man ever fleein ; and folks
wer’na then ignorant folk either, though they wer’na sae weel up
in some things as oorsells, ye ken. Further, hoo lang was man
blawn about by the win’ before he found out that win’ had
weight ; and noo that he has found that out he seems no far¬
ther forward with it than was Papin with his biler bilin banes.

Angus. — Ou ay ; but we’re gaun to gie the thing a lift
forward, ye ken. The folks lang syne did’na ken ony better,
and the folks noo might hear us ; and it’s ower soon to draw
comments upon oorsells, for we ha’na ta’en root yet, and, in¬
deed, where to plant oursells either for fleein or for lookin on
is no jist clear yet. It’s you that’s gaun up, ye ken.

Mack. — Oh, I’ll no be feared.

Angus. — But where does the weight o’ the air come in ?
I dinna jist see.

Mack. — Wherever it’s in motion ; and no till then.

Angus. — Then nae motion nae weight, is that it?

Mack. — No, but nae pressure nae resistance frae the
weight o’ air that the pressure has to put in motion. The
simple weight is raither mair than an ounce and a quarter to a
cubic foot ; the resistance is according to the pressure in
motion, so if ye can impose the pressure ye’ll be a’ right for
the resistance. Oh ye may jist as weel blaw on your fingers as
waff your hands — ye’ll no find onything oot that way.

Angus. — Weel, but what resistance do ye look for fraje
an ounce and a quarter o’ caller air?

Mack. — If the ounce and a quarter were there alone, ye
would hae to be gentle wi t, but as it canna gang oot o the
road without displacing its neighbours, who are as heavy as
it sell, it'll suffer compression in itsell equal to the resistance
that the whole of them offer to displacement, or to that much
o’t that they’re slow in yielding to.

AERONAUTICAL SOCIETY

Angus.-' — And hoo far out will it claim neighbours among
the surrounding ounce and quarters?

Mack. — Till among them they can balance the pressure ;
but hoo far out I raither think ’ll depend on the time allowed ;
and that’ll depend on whether the imposed pressure is seeking
mere passing support, or is bodily displacing air frae the front
to the rear of the body; and, in the latter case, much will
depend on the length o’ the body frae front to rear, and on its
form. I hae na got the length o’ kenning mair than that.
Could your hand no tell us something? Waff t again.

Angus. — Ou, ay, it tells me there’s something gey saft in
■the business. Its no the hand, and ye’re trying your head.

Mack.-'-Nu, na ; what ye’re calling saftness the learned
call mobility, and there’s no a bird among them a could flee a
yard if their road was na as substantial as ony railroad, and a
good deal smoother.

Angus. — But look ye : we’ll say the cubic foot o’ air
gives only a square foot o’ surface for the wing to rest on, noo
what weight o’ body do ye propose to allow for that square
foot o’ wing surface ?

Mack. — Weel ye see, if the wings are to be a’ in motion,
and none o’ them mere floats, we might put between twa and
three pounds on a square foot o’ wing. But dinna mistak, for
when fleein there’ll no be twa or three pounds on the square
foot o’ air surface, and as little will there be that weight on
the wings that press the air surface. D’ye understand ?

Angus. — Indeed I dinna — but gang on, I’ll follow. What
do ye do wi’ the weight, if neither the wings nor the air carry
it?

Mack. — Oh, but they do carry it — that is, the air carries
it — and the wings jist spread it out like on the air. D’ye see
noo ?

Angus. — No, I’m quite blin’.

OF GREAT BRITAIN.

Mack. — Weel then, we’ll suppose that the weight has
been got up, and is in fleein motion, say on a horizontal line,
which implies that there’s a force at wark opposing the
action o’ gravity, by mechanically developing in the air, come
upon as much resistance upward, as the weight has natural
tendency downward. Noo, as the weight is not allowed to fall
any, this tendency in it will be aye at zero, aye ready, but never
beginning, ony mair than if it were supported by this table.

Angus. — Yes ; but hoo do ye spread out the weight?
for it seems to me that wherever the body is, there also will be
the weight ; and ye surely dinna think o’ spreading oot the
body.

Mack. — Oh no. We need only to spread oot force equal
to the force that the attraction o’ the earth would uniformly
develop in the matter o’ the body. If we stop the attraction
from producing motion in the body, by transferring equivalent
motion mechanically to the sustaining wings, we hae the
weight o’ body still entire, but without the freedom o’ motion
earthward to make it dynamically sensible. And, as simple
weight is only the force o’ attraction between earth and body
made sensible in pressure — further, as the force o’ attraction
for a given weight is uniformly equal in value in equal spaces
o’ time, and we balance it by oor wing force, this wing force
need, in amount, be nae mair than the amount o’ force o’
attraction between earth and body for that time — so that the
faster the wings can travel horizontally in a given time, the
less need be the pressure on them to balance the uniform force o’
the earth’s attraction in the body ; for they’ll then get the sus¬
taining resistance o’ a greater surface o’ air than when travel¬
ling slower: and as there is only a definite amount o’ resist¬
ance wanted, the greater surface will have less to bear per
square foot. Noo do ye understand ?

Angus. — Honestly, no yet; for I canna get ower the

AERONAUTICAL SOCIETY

weight upon the table ; it has nae energy o’ motion earth¬
ward, ony mair than your fleein weight, but the table has to
bear it a’ the same. Jist tak’ the weight into your hand,
and tell me what difference would your hand feel if it were
fleein wi’ the weight.

Mack. — Hoots, man. If with the body in your hand
ye support your hand on the air and move it horizontally, so,
the extension o’ the air support will be equivalent to an exten-
tion o’ the hand, and as the force o’ attraction has dynamic
value only in relation to time, we have the force due to one
second of time distributed along the extended hand support for
•one second — that is, we produce or develop in the supporting air
in one second o’ time, dynamic resistance equal to what would
be developed in the weight if baith hand and air were re¬
moved. A weight resting on the hand is but a dead weight,
it’s the wings mak a’ the difference. If Sir Isaac Newton’s
apple had had wings in motion when it left the twig, he would
ne’er hae got the hint that has made us a’ wise men ; but we
might instead hae been soon a’ fleein, and wha would hae
bothered themsells wi’ railroads then ?

Angus. — Weel noo. I canna say whether ye be right or
wrang ; but hoo are ye gaun to get up to put it to the proof ?

Mack. — Wi’ a rin on the grand and strength o’ will,
maybe ; or maybe we’ll drap ower some brae-head to get a lang
slide on the air to gather speed; but ilia’na jist come to that
yet, and canna say.

Angus. — But what do ye mean to do about feathers ?

Mack. — T ha'na got ho far as thorn yet. I'm still only
seeking for first principles.

Angus. — Ye re no sae far advanced then a- some I read
o in the Society's last .Report; they hae got the length o leg*
and india-rubber.

Mack. — Ah, but that’s no on oor side o’ the" water.

OP GREAT BRITAIN.

The legs ye read o’ are French anes. Oor folk are using steam,
and they can dae -without a biler.

Angus. — Ay ; and I see they’re proposing to use a separa¬
tor, to get the oxygen oot o’ the air to save coals.

Mack. — Weel, weel, the mind ’ll no sit still; it maun aye
be on the march.

Angus. — I notice besides, that ane o’ the Members,
writin about the wave o’ expansion on the rear edge of a
floating wing, shaves gey near perpetual motion.

Mack. — Angus, what do ye call the motion o’ the moon
round the earth ? or o’ the earth round its pole ?

Angus. — Oh, if ye’re gaun to be sair aboot it we’ll let it
gang; it’s as feasible onyway as the motive force which anither
Member derived from his stick when he hit his fleein frames
as if he had been hitting a fleein cuddy ; but there noo, ye
needna speak. I’ll no say anither word on that score : and I
dare say a stick’s as gude a first principle as onything ye’ve
named yet ; there, that’ll dae noo, I’ve dune. There’s plenty
else we can speak o’ withoot fa’in oot aboot it : ye ken, I’m no
speaking in ill-humour. Ye hae had your say aboot the weight
o’ air, but it has yet to be made clear what use is to be made
o’ the 151bs. to the square inch natural pressure when fleein.

Mack. — Nane mair than to keep the weight what it is.
If ye gang up to where this pressure has its beginning ye’ll
find the weight has its beginning there too, for the natural
pressure is jist the value o’ the weight o’ column frae tap to
bottom — naething else.

Angus. — TTon nan that be. if a cubic foot n’t. a+ the bot¬
tom where the I .Mbs. i-. weighs milvnjie ounce ami a quarter;

Mack. — Jist because vc weigh it bv itsell. and leave the
column ubuue not o t lie count when weighing, for it has only
determined the density at the bottom. But ye’re surely no
needin to be told a’ that, ye were* lang enough at the schule.

AERONAUTICAL SOCIETY

Angus. — Oh, man, there was only Greek and Latin at the
schule where I was, sae ye maun hae patience wi’ me jist ae
step farther. If the bottom cubic foot o’ air is bearing a
pressure o’ 151bs. to the square inch of surface, surely ye have
to start this pressure into motion when ye move the air.

Mack. — Not if it be motion o’ displacement only, because
the compressive and expansive forces are in balance in the air,
and in mere displacement baith gang wi’t, leaving in the form
o’ sensible resistance only the inertia o’ the simple weight o’
the volume put in motion. If it wer’na for that what would
become o’ us when the win’ blaws?

Angus. — We would hae to gang wi’t tae, and pray it
would’na tak us near the water.

Mack. — Ye maun understand that the 151bs. pressure
becomes sensible force only when ye form a vacuum; the ex¬
pansive force then wi’ the compressive force as an abutment
on ae side, and naething on the ither, acts in the direction o’
the naething, like a spring of 151bs. power.

Angus. — And I suppose, in the case o’ a partial vacuum,
it would enter wi’ only proportionate strength.

Mack. — It would; and as the lolbs. balanced elastic
force is for the surface o’ the earth, and the density, and with
it the elastic force, increases every foot ye descend below the
surface ; if ye can bring pressure equal say to the weight o’
one foot extra of air column, to bear by way o’ helping the
compressive force, the expansive force at that point will be
- for the moment driven back upon itself by the mechanically
applied force, say from a bird’s wing, until it intensifies to
balance the applied mechanical pressure plus the natural
compressive force; 'but this must be quickly done to prevent
the mobility o’ the air come upon from acting outwards in free
displacement.

Angus. — Man, do ye no think some graphic experiments

OS' GREAT BEITAiV-

wi’ reds and blues ye ken, to distinguish ae kind o’ pressure
frae anither would help us baith?

Mack. — We hae had the real thing practising before oor
een lang enough : rowing birds and soaring birds, birds that
whirr and flee straight, and birds that flee in a’ manner o’
ither ways. What could we hae more graphic than that ?

Angus. — Hoots ay, man, we ken a’ that ; and there’s nae
end tae the poetry that’s been written about it, but can ye
no put the mechanics o’t in form. Hae ye ever tried ?

Mack. — Oh, the wee anes are ower quick, and the big
anes are ower far awa. There’s a fellow countryman o’ oor
ain, hooever, has scrapet their banes and measured the knots
and gullies in their shouther joints. And round aboot his
garden got to be famous for the evidences o’ devotion to
science, a’ in distress. Neer a cat need want its dinner there if
it could eat a sparrow wi’ its wings clippet. Ye see he wanted
to find out the fleein feathers.

Angus. — Could figures no hae served his turn as weel,
without ill using the puir things ?

Mack. — Ou ay; he used figures tae, at least he used
ane — the figure 8 — but it was only for a symbol ; and what
was a wheen sparrows, compared wi’ a question that was to
revolutionize the world.

Angus. — It was deil’s wark at the best; and ye ken the
sparrows are no the deil’s. I hope there are nae mair philoso¬
phers wi’ shears.

Mack. — I dinna ken ; but a knife can do some things
better than shears.

Angus. — Some things waur than wing clipping d’ye
mean ?

Mack.— Ay; but it was na by ony countryman o’ oor
ain. He wanted tae ken whether the beef o’ birds had extra
pith in it or no ; sae he ptrappit down a living bird upon a

AERONAUTICAL SOCIETY

table, and cut awa till be got the shouther muscles a’ bare,
and loosened frae ane anitber, and the elbow-joint, for conve¬
nience, disarticulated. The muscle twitched when it got an
electric shock, and he measured the livin’ force in the twitch
by means o’ weights tied tae ane o’ the sair ends.

Angu£, — Weel, a’ I can say is, if ye lay the foundations
o’ the science in the blood and suffering o’ the innocent, the
Lord’ll never prosper ye. Man, I jist wish my anger were o’
mair consequence — but let’s change the subject. Let’s talk
aboot the win’ that ye’ll hae to lay your foundations on. Will
ye flee against the win’ or wi’ it ?

Mack. — If the win’ be strong it will be easier tae gang
wi’t : if it be very strong there’ll be nae alternative wi’ a numb
machine but gang.

Angus. — Tae let it blaw ye alang like ?

Mack. — No indeed : if to begin wi’, ye were tae gang
slower than the win’, ye might lose control ; but that would
depend greatly on the form o’ your machine; and if at the
same rate as the win’, ye would be practically in a calm, and
the back o’ the wing would be nae stiffer to bear ye than would
air at rest, for the momentum o’ air in motion can become
sensible only in pressure o’ resistance to it. If going faster
than the win’, that would be equivalent tae starting frae a
point o’ rest in calm air, and the velocity additional tae that
o’ the win’ would be the working velocity for support.

Angus. — But ye dinna mean tae say ye learnt that frae
the birds ?

Mack. — No. for it’s seldom their business in life requires
tluMii to travel in dr a hurrv. or as far as the length o a gale.

Angus. — Bui* what aboot the ocean birds, don’t thev ave
keep head lo windward '(

Mack. — Aye when they’re no wanting tae gang the ither
way. But, speaking o’ the win’, jist look to-morrow at the

OF GREAT BRITAIN.

reek rising frae some lum tap, 'where there’s a column o’t the
width o’ the pot. If the win’ be moving horizontally at say
aboot the same easy rate as the column o’ smoke vertically,
ye’ll see the column bending, withoot much losing the form
that the pot has given it, and rise some height before the win’
takes it horizontally awa ; that’s owing tae the weight in the
rising column being, at the start, equal in inertia tae the weight
o’ the win’ in contact wi’t there, else would the win’ blaw
straight through the column.

Angus. — Windy observations on a lum tap; but I’m
listening. I’ll look up in the morning.

Mack. — Oh, but I hae some windier anes. In the late
gale, in crossing the West high bridge, I found mysell at one
part unexpectedly in a dead calm, though my head and
shouthers were above the wall. Resting my hand on the wall-
top, there was still nae win’ ; but on projecting my hand
beyond the outer edge I found that the win’ stopped by the
wall was being deflected upwards, and that the momentum o’
its weight in upward motion was forming an arch o’ resistance
tae the pressure abune the wall ; and for some height abune the
wall the arch could be felt as plainly as if formed o’ spouting
water.

Angus. — But ye surely dinna mean to mak ony sic com¬
motion when ye’re fleeing ?

Mack. — No, for we’ll be fleeing an the brigg was na.

Angus. — Is that windy arch onything like the wave o’
expansion we had the remark aboot ?

Mack. — No, for the arch was formed by two currents o’
weight in cross motion ; whereas the wave will act by the
expansive energy of the compressed volume o’ air, in much the
same manner as the expansive force acts in filling up a partial
vacuum. Ye’ll take notice, hooever, that the wave energy has
nae concern wi’ the 151bs, natural force, but only wi’ the

AEBOtfAtiTlbAL SOCIETY

sensible pressure distinct from it, and due to the compression
o’ the sustaining volume by the wing plahq ; consequently the
energy o’ the reaction and its velocity will be correspondingly
less than when a vacuum has to be filled up.

Angus. — Ay, but stop a bit. I’ve read somewhere that
sound travels on a wave moving at the rate o’ mair than a
thousand feet a second, and ye’ll maybe have noticed that when
a big gun is fired the windows in the neighbourhood rattle in
their casements aboot the same instant that ye hear the gun.
Noo, hoo does your wave o’ expansion stand in relation tae that
ane ? It seems to me they belang tae the same family.

Mack. — I’ve nae doubt they dae ; but ye’ll observe that it
is not necessary for the shaking o’ the window that the weight
o’ the whole body o’ air between it and the gun is blawn
against it. Drap a smooth pebble into still water, and the
waves that gang circling oot frae the spot will explain my
meaning : any light things floating in the way will show that
they are waves o’ oscillation only. In the case o’ the air wave
caused by the gun, the window arrests the oscillation and
consequently shakes. Ye’ll observe, further, that there’s a
succession o’ waves frae the centre where ye dxapped the
}<ebble, because the trough in the rear o’ the wave is below the
original mean level o’ the water, and so develops a succeeding
wave ; and similarly in air, where in place o’ the height and
hollow o’ the water wave form we hae rarefaction and com¬
pression in rapid alternation.

Angus. — But you don’t mean tae say there’s naething but
oscillation in the track o’ the shot?

Mack. — No ; there’s local disturbance there, jist as there
is in the track o’ a bird’s wing.

Angus. — Then oot frae the local disturbance o’ a bird’s
wing we may look for oscillation I suppose ?

Mack, — Seasonably we may, as the sound o’ a flapping

OP GREAT BRITAIN.

sail travels as fast as that o’ a gun, big or little, only it thins
out sooner, because the weight o’ the oscillation is less. If the
disturbance o’ the displacement under a bird's wing wer’na
local mainly, so as to be governed by the common law o’
gravity, but had its displacement-motion propagated wi’ the
velocity o’ the waves o’ sound, this motion and the motion o
the wing would na correspond at a’.

Angus.- — Weel, wi’ as many waves o’ oscillation as there’ll
be in say a big flock o’ American pigeons, hoo dae the bottom
birds get on at a’ ?

Mack. — I dinna think it would be safe for me tae gang
ony farther in explanation. There’s Tyndall, ye ken.

Angus. — Oh, man, dinna fear, Tyndall would na mind ye ;
but ye’ll be safer on the fleein track wi’ the local disturbance ;
ye’ll there be as wise as himsell maybe. As for mysell, I wish
ye were talking aboot things that the mind could form some
image o’. Let’s hear something mair aboot the handles and
the taps that are tae keep a’ the energies ye speak o’ in fleein
order.

Mack. — Ay, but we hae na got the length o’ needing
handles yet. We maun first arrange the fleein order before we
can make a picture o’t.

Angus. — Aweel, I’ll wait till the picture’s ready; and,
mind ye, let’s hae a man in’t this time. But surely ye hae
formed some mechanical notion o’ hoo tae put the energies tae
use, for withoot something o’ that sort they can be o’ nae mair
profit than the moral excellencies wi’ naebody tae claim them.
Is your machine tae be lang or short, round or flat ? or hae ye
the bird in your ee for a pattern ? Puir things, they’ll hae a
sair time o’t for a while when ye get up among them.

Mack. — Weel, the machine and the bird’ll baith flee, and
they’ll baith mak the road that’s tae sustain them by com¬
pressing, in the same fashion, a layer o air tae the density

AEBONAUTICAL SOCIETY

suited tae their weight, in muoh the same way as a garden
roller, in motion, compresses saft grand ; but I don’t know
that the bird and the machine’ll hae onything else in common.

Angus. — That parallel has some weight onyway, and
deserves consideration. Od’ man ; I never thought o’ a garden
roller in that connexion before. I’m afraid, hooever, ye’ll no
be able tae carry your parallel very far into the question.

Mack. — Oh it’s no necessary. Ye said ye could best
understand what your mind could form some image o’, and I’m
no against images mysell. A short or narrow roller on saft
ground would only mak a rat track for itsell ; whereas a long
roller o’ the same diameter and weight, by spreading that
weight ower a wider path, would gang easy on the surface.

Angus. — But what in the air answers to the rat in the
grand ?

Mack. — Oh, there can be nae rats in the air road : ye
would come doon through the road if ye were tae narrow your
footing there.

Angus. — Not I, ye may be sure o’ that : ye’ll neer get me
tae gang up tae roll the win’.

Mack. — Wha’s thinking o’ rolling the win’ ? Sliding’s
the word.

Angus. — What made ye speak o’ a roller then ?

Mack. — For the sake o’ the image, and because the
question o’ lateral extension o’ surface applies tae the air in
fleein, as weel as tae the earth in rolling, and fleein’s sliding,
as sure as rolling’s circling round a centre ; and as the air road’s
no made tae hand, and the air has tae be come on wi’ the
suddenness o’ a surprise, to be pressed on lightly and awa
before it has had time tae get oot o’ the way, it seems mair
than likely that, for the light short tread, the sliding planes
answering to the wings o’ a bird will be narrow measured in
the direction o’ flight, and laterally long, and the length
laterally shall be the measure o’ the width o’ road.

OF GBEAT BRITAIN.

Angus. — But if ye mak your wing planes sae narrow
that’ll become o’ your wave o’ expansion that’s tae dae sae
much on the rear edge ?

Mack. — Oh, the wing planes’ll no be narrower than the
wings of the bigger birds, and the wave, I expect, acts in them,
though I’ve never seen’t.

Angus. — Bui the lateral extension’ll mak them sae supple
that I fear the wave would be at a loss in places tae ken the
rear edge frae the fore ane.

Mack. — Oh, we can clip the ends if we see ony uncertainty
o’ that sort, and jist gang a wee bit faster tae mak up for
what’s cut aff.

Angus. — But ye’ll need sae many o’ them, ane coming
hard on the heels o’ anither I suppose, that I dinna see hoo
the air can be come on wi’ the suddenness o’ the surprise ye
speak o’ wi’ ony mair o’ them than the nrst ane. A bird has
only twa, ye ken, ane on each side.

Mack. — Man, the machine a’thegither ’ll be sae unlike a
bird, ye can hardly reason frae the ane tae the ither.

Angus. — Where does the difference begin ? Is it at the
strings and whalebone or at the man ?

Mack. — Wi’ a thing that has na had a beginning yet it
would be hard tae say.

Angus. — Aweel, its clear that I’m no tae get the picture
o’ the thing the night. A lum tap, and a stane brigg, and a
garden roller : there’s nae uncertainty aboot them onyway ; and
I suppose ye’ll be haudin at them till, wi’ the light short tread,
the touch and awa, ye gae aff to whustle among the albatrosses.
Lets ken when ye’re a’ ready, for I can hooray weel.

Mack’s mind got oot o’ harness when Angus left, and ran
awa tae play wi’ some fancies that had been patiently waiting
for its leisure. The night was na cauld, but it was dark-; and

AEBONAUTIOAL SOCIETY

frae the black darkness spread oot below cam up the surging
sound o’ an ocean o’ billows on* the march, before a dour
droning gale.

Owerhead were clouds no far aff. In front, so near that
in the dark they seemed within reach o’ the hand, were forms
vague and undefinable in continuous whizzing motion, and the
whizzing sound made known tae him that ''there were similar
forms behind.

It was like travelling in a dream, and hoo far he might
hae travelled, or hoo lang, he was na thinking, when the door
opened, and in cam Mrs. Mack tae ask him if he did na think
it was time tae gang to bed. While she was yet speaking his
mind crept back intae its harness again, for the dream was at
an end.

II— A FEW WEEKS LATER.

Angus. — Weel, Mack, ye’re busy as usual I see, aye
sowing and harrowing in ; but I forget if I’ve ever seen ye
reaping. However, this is Mr. Howie, who believes in the air
road, I think even mail- stoutly than yoursell, for he sees nae
difficulties.

Mack. — I’m glad to see ye baith. Draw in chairs and sit
ye down.

Angus. — Ah, weel, we ll jist sit down on the edge o’ them,
for we hae na lang to stop. I would hae waited till we had
mair time, but Howie would’na. He thinks that the hour has
come, and the world’s jist waiting for the man, and he’s in a
hurry tae get forward,

OF GREAT BRITAIN.

Howie. — Nothing of the sort, Angus. I thought the
hurry was your own.

Angus. — Oh, it’s ower soon to blaw the horn yet, is’t?
My mistake has na come far. My arm felt as if linking wi’ a
blawn blether when ye were yarning about air dynamics in my
lug on the road here ; but let that pass. The twa o’ ye at it
noO. Howie wants to ken if ye’re doing onything at present
in the fleein line.

Howie. — Well, I do ; but I hope the answer wont be
quite so blunt as the inquiry.

Angus. — Hout man, dinna fear. Mack’s maist as fou o’
the thing as ye are yoursell.

Mack.— It’s a quiet founess then, for I’ve done naething
since you were here last.

Angus. — Howie’ll beat ye in the race then ; and its a
grand prize that’ll be given tae the winner : a monument at
least.

Mack. — There’ll be mony a ane ending the race, as ye
call it, that did na begin it ; and monument or no, there’ll
maybe be mony a ane giving the world a thankless gift o’ half
their days that canna weel afford it, no tae speak o’ the sair
heart that may be left wi’ them when they see naebody taking
notice o’ their absence at the winning post. Better they had
taken their imaginations tae the grundstane than have let it
Tun them into sorrow o’ that kind.

Angus. — Man, surely your wark has na been gaun weel
wi’ ye the day, that ye’re talking that way.

Howie. — Its spoken in reason though.

Angus. — Ay, wi’ reason o’ the kind that would have left
us still feeding our horse-power wi’ beans. The back-ground
o’ effort that never gets to the front is to be pitied nae doubt ;
but there’s poetry in’t man, if man had but an ear for’t, and
the Lord kens the world’s fou o’t. An empty meal-poke, and

AERONAUTICAL 80CIETY

an abstracted mind, that’s aye awa trying to see things before
their time, gang weel thegither ; but the grundstane Mack
speaks o’ would rub poetry out of the companionship and leave
naething but sair places.

Howie. — But, Angus, the background cannot be aware of
this compensation to their disappointments.

Anoub. — Oh, I never was that much in the background
tae ken whether they are or no. I’m no in the way of sair
hearts. If folks dinna play fair I soon let them hear o’t.
But we did na come to speak aboot that. Howie wants to
speak to ye aboot hoo to get up the way the birds dae.

Howie. — I’ve been simply wishing to know how birds fly.

Mack. — I fear you are not alone in your wish. I’m some¬
what at a loss mysell : there’s sae many different kinds of
fleein.

Anoub. — Oh, Howie’s no particular, he’s willing to employ
ony o’ their ways.

Howie. — I’ve been reading Marey on the motions of the
wing, but wish to know how support from the air is derived
from these motions.

Anoub. — He wants to ken, in fact, in what kind o’ fashion
the stour would rise, supposing the air road were a dusty ane.

Mack. — I doubt stour’s no the proper word, for if the air
that has been compressed by the forepart o’ the wing reacts on
the flexible rear edge, as there’s some reason to believe it does,
it should not have much motion left in’t tae raise onything like
stour when the wing has passed.

Howie. — My difficulty is this. I am at a loss to know
how the force of gravity in a falling weight is expended on the
air when wings are used. From the wings in motion we get a
certain pressure, but how does this pressure stand in relation
to the force of gravity ?

Mack. — Weel, the pressure is the resistance tae displace-

OP GREAT BRITAIN.

ment o’ the weight o’ the air come upon. The force o’ inertia
o’ the weight o’ air displaced balances the force o’ an equal
weight o’ the displacing body, sae that when, at a given speed,
the force o’ inertia in the air displaced becomes equal tae that
o’ the whole weight o’ body, the displacing speed is found tae
continue uniform, because the inertia forces are balanced.

Howie. — Yes ; but how can we, from the elastic pressure,
determine for weight of air displaced ? for the pressure is con¬
stant, and it is not clear how constant pressure can be an
equivalent to the displacement of a weight of air whose volume
must take time to get out of the way.

Maok. — The resistance is as constant as the pressure.
The imposed pressure performs work in the displacement o’ air,
and has in itsell tae be constantly renewed by fresh force, even
as the air equivalent is renewed by fresh air come upon.

Howie. — Yes ; but supposing the weight of a bird to be
lib., will that require pressure amounting to lib. in the wings ?

Mack. — If it did the bird could not fly. The bird has
only, in a given time, say 1 second, tae develop in its wings
dynamic force equal tae the dynamic force that gravity would
develop in the lib. weight in that time ; but tae save further
explanation at present I will give ye some notes bearing on
the question, that ye may examine them at your leisure.
Ye’ll see they’re already in print.

Angus. — Oh, Howie ’ll no understand them. Talk them
tae him, man, and leave oot the figures.

Howie. — We’ll set the figures to music, for Angus’s
bag-pipes.

Angus. — And we’ll tak you for the win bag : ye’ll be o’
some service among figures then.

Howie. — Whose wind will be in the bag in that case,
Angus ?

Angus. — Gang on wi’ your crack ; time’s pressing, ye ken.

AERONAUTICAL SOCIETY

Howie. — Well, a body falling freely in space, and the
same body falling in air, would be under very different con¬
ditions as regards velocity. The velocity of the body falling
in air is retarded, and at length becomes uniform with the space
fallen in a given time ; but it is not so with the body falling
free from air. Now, in reckoning the actual energy, or force
accumulated in the weight in a given time, by taking the
actual fall in air, and for the same space of time in a Vacuum,
I cannot bring the two cases to common terms.

Angus. — Twa’s ower many for ye' to manage at an’ce,
Howie. Tak them singly and gang lightly.

Mack. — I see your difficulty ; but the energy is in the
final velocity, irrespective of the distance fallen to acquire it;
and in the case of air, as the velocity at any point determines
the acttlal energy of the pressure on the air, we refer it only
relatively as to a standard rule, to a similar velocity in a vacuum
of free space, the distance fallen in the vacuum determining
the velocity. For convenience of observation of the uniform
acceleration of gravity, it is usual to have two unequal weights
hanging from the two ends of a line which passes over a
pulley delicately balanced. The gravity of the slight excess
of weight oU one side forms the motive power that sets the two
weights in motion, the lighter upward and the heavier earth¬
ward; and the motive power is so small compared to the
inertia resistance of the whole weights it has to put in rUotion,
that the velocity, though uniformly accelerated as in a free
fall, increases with slowness that bears a distinct relation to
the ratio of the excess weight to the whole.

Angus.— But what does the excess weight correspond to
in a case o’ fleein ?

Mack. — It must be looked for in the weight of the fleein
body, only before it has got complete air support, and has, therb-
fbVe, an unbalanced downward tendency. If in the Worn o^

OF GREAT BRITAIN.

the lighter restraining weight we substitute air resistance
beneath the motive-power weight, and make that weight a
wing plane, we are free to reason about the inertia of this air
resistance as we would about that of the weight it took the
place of.

Angus. — Mack disna ken ye as I do, Howie, but 1 11
straighten it all out for ye on the road hame. We can jist'
noo, at least, look wise and say naething. I’ve known a cheap
advantage got that way whiles. The talking folks begin then
to tak care what they say, out o ’respect like. But, Mack,
that’s only between Howie and mysell, ye ken. We re baith
waiting on ye.

Mack.— In the case ©f the wing-plane pressing upon air
ye may not, in relation to time, be able to bring the retarded
velocity to common terms with the free velocity of gravity, but
ye can the spaces fallen up to the moment when the velocity
of the wing-plane becomes nearly uniform ; and the tabulated
results of one of M. Didion’s experiments, given in Bennett’s
Morin, shows this. If, on the shorter of the two legs of an
L figure, ye mark off the timed spaces actually fallen, and on
the longer the spaces due in natural gravitation in the same
times, ye will find that lines connecting these space points
will run parallel from the start at zero to the point he reached
near uniform velocity of plane, at the end of 2 seconds of time.

Angus. — Ye say the time of the experiment was 2 seconds.
Weel, if dynamic force rules in the case, will the wing-plane
falling 2 seconds in air hae developed force equal to the force
it would develop in the same time falling in a vacuum ?

Mack. _ Well, in this experiment the final velocity was

only about one-third the velocity due to free gravity, and we

can compute by the velocity only.

Angus. — At that rate it seems to me that the air force
could be only about a ninth o’ the free space force, and, at the

AERONAUTICAL SOCIETY

most, ye hae only the weight and its equivalent air pressure,
equal 2. Noo, what has become o’ the difference ?

Mack. — At the end of the first second the acquired
velocity was about one-half that due to free gravity, the space
fallen being in about the same proportion. Close to the start
Wfe find the space fallen in the higher ratio of about six-tenths
of the space for free gravity, and the acquired velocity would
no doubt, correspond, though it is not given. We here then
see the difference beginning at the start, where the velocity is
small and the force consequently feeble; and to bring the
difference to a balance with the force developed in free gravity
we would have to estimate the whole work done in the res¬
pective eases in the given time.

Angus. — Weel, we’ll no bother wi’ the estimate, we’ll tak
your, word for’t. If ye could give us an estimate o’ fhe
difference wi’ a man looking out o’t ye might depend on our
keeping mind o’ what ye said.

Mack.— No doubt I would if I could, Angus, but I hae
na finished wi’ what I was saying. The small velocity at the
start shows, very sensibly, that the actual full weight of the
wing-plane is not borne by the resisting air yhen the weight
first begins to move, for the weight requires time to get up its
speed, and the resistance of the air is according to the speed of
its displacement. The attraction of the earth has had the
same time in both the cases that concern the difference, and
is a uniform force, irrespective of whether the body has motion
in it or is at rest ; and as there is only the air resisting, the
air must have had the force transferred to it that otherwise
would have accumulated in the weight ; but we have already
had some talk on that matter.

Angus. — We have, and dinna begin again. I think, Howie,
we maun gang. I have tae catch the night’s post, and I doubt
I’ll have tae rin.

OP GREAT BRITAIN.

Howie. — There are many other points I would like to
speak of, but we may have another opportunity.

Angus. — He means to say, Mack, he feels nae nearer
fleein when he’s gaun awa than when he cam. Your philosophy
has na been pictorial enough. He would raither hae found ye
up tae the knees among shavings, wi’ wings at least ready for
the glueing ; and I’m no sure but a glue-pot would hae made
things livelier. I’m kind o’ disappointed mysell.

HI— EXPERIMENTAL BELIEF.

Angus. — Weel, Mack, hoo are ye the day. A bonnie
afternoon is’nt it ? I’ve jist been givin the weans here a walk
on the hill-side. Man, but it’s pleasant wi’ the sun shining
and the wind blawing wi’ summer saftness. The heart feels
that glad and cheery that grey hairs gang for naething in the
thoughts. I was wishing ye had been wi’ us ; but, maybe, a
man needs tae be a faither before he can enjoy himsell among
bairns as I can, and mine are nane o’ the quietest. I’m
thinking some o’ them’ll need some room tae work in when
their beards are grown. I’m doubting they’ll be asserting
the rights o’ man before the rights o’ their faither hae quite
dune wi’ them.

Mack. — Man, I envy ye.

Angus. — Ay, in a contemplative kind o’ way ; but they’ve
a’ had the measles and the hooping cough, and there’s naething
wrang noo but broken windows, and arms and legs growing
faster than their clothes. Ye’ve only tae look at Tommy’s
face tae ken wha broke the windows.

AERONAUTICAL SOCIETY

Mack. — Eh, Tommy, man, but ye’re beginning your
sorrows early. The tailor maun gie ye pouches tae keep your
hands in, and ye’ll no break windows then, ye ken. But here,
my wee man, here’s a ball I got for ye yesterday ; ye’ll no
break ony wi’ that ane, and there’s a whustle in the air-hole.
But what’s that ye hae got wi’ ye, Andrew ? Let me see’t ?
Is’t a new kind o’ windmill, or what is’t ?

Andrew. — It’s an ariel.

Mack. — This is no o’ your ain devising I can see, Andrew.
A thin card-board hoop, centred wi’ thread on a light rod near
one end, wi feathers stuck sloping oot frae the hoop edge,
Angus, did ye manage in your walk tae get this up ? I’m sorry
noo I was na with ye.

Angus. — Ay, I canna say we did na ; but there’s something
no yet thought oot properly.

Mack. — That s no tae be wondered at ; but had it ever
far tae fall ?

Angus. — Weel, I intend to mak the next ane lighter. I
think that s what’s needed before we begin tae speak aboot
results.

Mack. — Ay, ay : we’re no needing ony mair information
aboot the force o gravity. We want sustenance noo. But
which end gangs first : the plain edge o’ the hoop or the
feathered edge ?

Angus. — The plain edge ; and ye’ll see that the feathers
are set tae act screw-propeller fashion, at least they were when
we left hame ; but, man, it was only to please the bairns.

Mack. — Ay but, Angus, I’m much mistaken if ye were na
thinking a while by yoursell. withoot the bairns being in your
mind. The feathers here tak rank wi’ the outer ends o’
propeller blades, the length o’ the feather answering for the
breadth o the blade : but, man, they’re far ower long, and ye
hae set the wrang face o’ them tae the pressure. Ye see the

OF GREAT BRITAIN.

rib o’ this feather’s no in the middle. Ye should hae had the
broader side o’ the membrane outwards, for the narrow side,
being stiffer, should come first on the air ; but I see ye hae set
some right and some wrang. Why your feathers are a’ rights
and lefts, and some o’ them are tail anes. Man, the air would
hardly ken which way ye wanted the thing tae gang.

Angus. — Weel, ye see, it was’na a fleein bird they were
got frae, and the theory needna fa’ out wi’ the feathers, for it
disna appear tae be a fleein ane either.

Mack. — Ay, but look ye, if the feathers had been o’ the
right sort, and o’ a third o’ the length ye hae them, wi’ the
flexible side o’ the membrane inclined outwards, ye would hae
got some pressure outwards upon the surrounding air, getting
new air at an angle laterally as the thing advanced, and that
would hae given it baith sustenance and steadiness on its path.
If the tip o’ a bird’s wing did na bend so as to direct some
pressure laterally, it would lack steadiness in a straight course
and power in turning. By keeping the feathers here short in
the direction o’ their motion, which would correspond tae a
narrow propeller blade, the air that is come upon finds that the
end o’ the feather has passed and got a’ it needs before the
pressure has had time tae free itsell by lateral diffusion, and as
this diffusion would cause motion in the surrounding air, the
long draggle ends ye hae been using would, as they cam up, find
the firmness o’ the road sae much lessened as tae be nae road
at a’ tae speak o’.

Angus. — Oh, they did na lang want for support when I
gied them their liberty, and there was nae diffusion worth
considering ; but if ye like I’ll mak ye a present o’ the whole
apparatus, motive power bobbin and a’, tae work your improve¬
ments on.

Mack. — Man, but I hae nae weans tae be an excuse like
when trying ’t. Folks would think I was in earnest gaun

AERONAUTICAL SOCIETY

alane. Besides it is not the form I would adopt were I in the
way o’ experimenting.

Angus. — Let’s hae your mind on the matter and ye shall
hae baith the weans and my sell at your service. Weel hae a
fleeing machine this time surely, Tommy.

Tommy. — And will’t gang ower the trees ?

Mack. — Would ye like tae see’t gaun ower the trees,
Tommy ?

Tommy, — Yes, this ane did na ; but faither said he would
mak a big ane some day and tak me in’t.

Mack. — But the birds would laugh at ye, and ye might
fa’ aff, ye ken. Ay, ye may look at your faither. There’s
naebody but birds gang ower the trees.

Tommy. — But faither said he would tak me.

Mack. — I doubt, Angus, ye’ll hae tae keep your word here.
When the bairn has faith in his faither sae far as that there’s
nae help for’t, but flee ye maun tae save his faith, for, man,
it’s precious. Ye’re weel aff to hae somebody tae believe in ye.

Angus. — Ye maun help me a’ ye can then. Ye put the
case in that light would mak me risk mair than birds laughing ;
and ye ken a body’ll no can keep the thing in a corner till a’s
ready. What kind o’ form is’t ye were saying ye would adopt ?

Mack. — Oh, I was only speaking frae the easy side o’ the
question. That’s the side the maist o’ folk are speaking frae
noo, and I canna say that I’ve ony positive idea o’ the thing
that’s wanted.

Angus. — Man, what think ye o’ the wave o’ expansion
we’ve had the talk aboot ? On the rear edge o’ the wing ye’ll
mind. We would jist need some lithe frame-work, and a dozen
yards or sae o’ holland, tae fit us up.

Mack. — Ye’re joking surely ?

Angus. — Faith, I’m no sure if I am. I was watching
some what ye call soaring birds, big anes, the ither day in the

OP GREAT BRIT AIK.

course o’ my travels. They were aye ganging, and there could
be nae magic in their performances, naething but their twa
wings, and natural aptitude in the way they held them. Man,
I never saw sic easy work sae simply dune.

Mack. — But, Angus, the simplicity ye speak o’ is proving
mair difficult tae comprehend than the laborious style o’ rowing
birds. Ye had better try some ither example where the me¬
chanical forces are mair apparent. It would be hard tae find
a mechanical equivalent tae the organic sensibility operating
through the shouther joint o’ the soaring bird.

Angus. — Mechanical forces and laborious style ; that
means motive power and weight o’ engine essentials. Tommy,
wi’ a’ that tae carry I doubt we’ll no can baith gang thegither,
we’ll be ower heavy.

Mack. — Hout man, dinna talk that way ; ye can jist gang
wi’ the fewer coals.

Angus. — The natural aptitude can gang withoot ony coals
at a’ ; and gang sae simply, that I was only surprised that nae
ither body’s aptitude than the birds’ had yet been put in use.
But, Tommy, my man, never mind. If your faither disna see
the way tae tak ye, ye’ll maybe some day tak your faither.

MACK SOLILOQUISING
When Angus has left him again alone.

A trouble of the mind, this lingering thought of flying ;
a central weakness in it, like a child in a tramping company.
A vagary, ill at ease in presence of the judgment, that knoweth
not how to fit it in, and cannot well allow it to stay there, and
yet cannot bid it go, for the breadwinning forces seem but dull
fellows after all when looking from them to it. An ancient dream,

AERONAUTICAL SOCIETY

seeking anew to find a voice among the thoughts to give it
utterance ; but the minds it fain would interest will not dream,
or are unwilling to own that it hath seen encouragement to
visit them.

Over the watery waste and along the ground, a weary way
to where many of our best people, widely wandered from our
midst, are outlying, and now and again in places becoming lost
to knowledge, so that we know not whether they be dead or living.
An open highway to them in the air, but no one on it. Faith
rules in other matters, and according to faith must it be here,
where the eye sees not the road that has to be travelled, and
where the action of belief is needed to develop its reality.

M. Paul Bert, President of the Societe Fran^aise Aerienne,
is the author of Experimental Researches upon the influence
exercised by changes of barometric pressure upon the Phenomena
of Life, and is this year the recipient of the grand prize biennial
of the Institute of France. The work itself contains results
of the highest importance to aerial navigation.

The following extract is taken from the November Bulletin
of the Society’s proceedings, by James Glaisher, F.R.S. : —

“ The results obtained by M. Bert bring to light this
remarkable fact, that, according to the proportion employed in
respiration, oxygen becomes either an aid to life or a poison.

OP GREAT BRITAIN,

AEBONAUTICAL SOCIETY

“ The apparatus used by M. Bert for these researches was
placed at his disposal by Dr. Jourdanet. One apparatus
employed consisted of two closed cylinders of thick iron, com¬
municating with an air-pump set in motion by a Lenoir
movement.

“ In one of these cylinders Croce-Spinelli, Sivel, and
M. Bert himself tested, in their own persons, the effects of a
rapid diminution of atmospheric pressure. M. Bert, by the
respiration of oxygen, submitted therein to a pressure of 9-44in.
of mercury, which, fatal as it would have been without this
precaution, caused him not the slightest inconvenience.

“ Respiration, it has thus proved, might be maintained at
a height of about five miles by absorbing 610 cubic inehes of
oxygen per minute.

“ The first ascent performed by Croce-Spinelli and Sivel,
in 1874, attending to the instructions given by M. Bert, suc¬
ceeded perfectly and gave important scientific results, the two
aeronauts describing, on their return, the great advantage they
had derived from the inhalation of the oxygen.

“It unfortunately happened that when our colleagues
made their ascent on the 15th April, M. Bert was at Auxerre.
Sivel was unwilling to wait for his return. The two adventurous
friends, trusting to their own intrepidity, carried with them an
allowance only of 140 litres for each, that is to say, sufficient
for 14 minutes only. M. Gaston Tissandier, who had never
taken part in a high ascent, suffered himself to be guided by
his colleagues.

“ The aeronauts, wishing to economise the oxygen, reserved
it for the greater heights of their ascent, and did not begin to in¬
hale it soon enough. Now, the ill effects experienced in balloon
ascents is insidious, and when the explorers wished to have
recourse to these means of safety, they found themselves unable
to raise the tube to their lips.

OF GBKAT BRITAIN.

“ The death of our friends is in itself therefore an example
of M. Bert’s theory, and shows that if we hope to continue the
series of extreme high ascents, it will be necessary to furnish
aeronauts with automatic apparatus for the inhalation of oxygen.

“ The institute has fully comprehended the importance of
M. Bert’s work upon the influence of barometric pressure.

“ M. Lefuel, presiding at the Annual General Seance of
the Five Academies, expressed himself in the following terms : —

“ ‘ A biennial prize of twenty thousand francs is, by turns,
accorded to that work or discovery most calculated to reflect
honour upon, or be of use to, the country.’

“By the terms of the decree of the 12th of December,
1860, this reward, the most honorable that could be to national
emulation, is decreed by the institute upon the successive
nomination of each of its classes. This year, upon the pro¬
position of the Academy of Sciences, it has been granted to
M. Bert, Professor at the Sorbonne, for his work upon the
influence of barometric pressure upon the phenomena of life.

“ In granting such a recompense to the numerous and
varied experiments of M. Bert, to his useful and long-continued
studies pursued for many years under very difficult circumstances,
you have. Gentlemen, to speak in the name of the Academy of
Sciences, represented by M. Claude Bernard, you have, I repeat,
made clear to every one the importance you attach to the
progress of pure science and to the discoveries of scientific
truths. These last are always fruitful, but time is required to
develop and mature results. The discoveries of M. Paul Bert
possess this eminently scientific character of certainty and
precision, which at once places them in the front rank of the
greatest physiological discoveries of our epoch.

“ Not only is the Society of Navigation Aerienne honoured
in the person of its President, but it derives satisfaction from
the fact that the biennial prize has been decreed for a subject
bearing upon aerostation,

AERONAUTICAL SOCIETY

“ The time has long since passed when thought and
enterprise spent in the service of aerial navigation were looked
upon as folly. It is certain, however, that the study of
aeronautics is not exempt from followers who, speculating upon
the credulity of the public, endeavour, as we have seen lately,
to abuse its confidence by illusive prophecies : but if amongst
those engaged upon aerostation there should be charlatans, we
should, under no pretext whatever, admit them as colleagues.
There are others, it may be seen, that France delights to
honour, like our President, M. Bert, or that France deplores,
like our colleagues, Croce-Spinelli and Sivel.

“FELIX CAEON.”

“ Monthly Notice for November, 1875, of the
SocUtA de la Navigation Aerienne."

OF GREAT BRITAIN.

EXPERIMENTAL RESEARCHES,

Prof. M. Paul Bert, Deputy of the National Assembly,

UPON THE INFLUENCE EXERCISED BY CHANGES OF ATMOSPHERIC
PRESSURE UPON THE PHENOMENA OF LIFE.

Translated by .T JAIMES GLAISHEE, E.it.S.

The various notices I have had the honour of presenting
under this title have had the effect of demonstrating that
changes of barometric pressure, if we except very rapid and
great decompressions, have no physico-mechanical action upon
animals and vegetables, but influence them exclusively from a
chemical point of view. Below the normal pressure of the air
too feeble tension of oxygen tends to promote asphyxia : above,
too strong a tension tends to increase those formidable accidents
which I have designated, somewhat paradoxically I admit, by
the expression, poisoning by oxygen ; and hence the conclusion
at which I have arrived, that all danger may be avoided by
varying the oxygenous richness of the air inversely to the
variation of pressure. Thus, as regards the diminution of
pressure, the mal des montagnes, and the mal des aerostats, I
have said —

“ If aeronauts, stopped in their vertical career not by the
failure of the balloon’s ascensional force but the impossibility
of maintaining life, should wish to ascend to a greater height
than has yet been done, they will be able to accomplish their

AfiEONATJTIOAL SOCIETY

desire by carrying with them a small balloon filled with oxygen,
to which they will have recourse when suffering from the
rarefaction of the air.”

On the 20th of last March, at 2h. 37m., I placed myself in
my great apparatus of decompression, within which the tem¬
perature was 53- 6°, and the atmospheric pressure 29’69in.
Under the influence of the pumps, which maintained a current
of air with a constantly increasing pressure, at 3h. 10m. I found
myself at 1 7'72in., and maintained myself until 4h.20m. between
that pressure and that of 16'06in., values corresponding to
heights of 13,431ft. and 15,712ft. respectively. I then
reascended to the normal pressure, which I attained at 4h. 45m.

On arriving at 17'7in. I began to experience symptoms of
the mal des montagnes. These continued to increase up to the
moment of the decompression, and consisted of a feeling of
heaviness and weakness, with sickness, fatigue of sight, general
indifference, and inertness of mind difficult to surmount. On
attaining a pressure corresponding to the level of Mount Blanc,
it seemed to me impossible, after counting my pulsations during
the third of a minute, to multiply by three the number found.
A little later, having lifted my right leg, it was seized with
convulsive tremblings, which extended to my left leg and lasted
some few minutes. My face was then slightly congested, and
the temperature underneath my tongue, taken with the greatest
care, presented an increase of 0T to 0-2 of a degree. My
maximum respiratory capacity, measured by the spirometer,
had lessened in the relation of 17 to 12. Lastly, under 17’7in.
of barometric pressure, I found it absolutely impossible to
whistle.

These facts, however, I do not here insist upon. The inter¬
esting point of my experiment is as follows : —

I had taken with me a little balloon of nearly pure oxygen.
On arriving at nearly 16#9in., with very manifest distress and

or QBE AT BBITAIN.

a pulse which, from 62 pulsations, had gradually increased to
84, I made an inspiration of oxygen. Almost immediately my
pulse fell to 71. It soon reascended, the more so that I made
an effort to breathe into the spirometer, and reached 100 only
to redescend spontaneously to 90. The same experiment was
repeated ten times during my stay, and each time the same
result was produced.

Each respiration of oxygen was accompanied by a very
disagreeable eblouissement. Having on one occasion made three
consecutive inspirations, I very nearly fell from my chair, seized
with vertigo ; but this effect soon passed off and was followed by
a short period during which all sense of sickness disappeared
and my pulse reascended. The violent sensation immediately
following the inspiration of oxygen is easily explained ; in fact
my oxygen, under a pressure of 16‘9in., had a tension corres¬
ponding to that of oxygen contained in the compressed air of
2 5 atmospheres. I therefore passed suddenly, as regards
chemical tension, from nearly 1-5 atmosphere to 2'5 atmos¬
pheres, a shock which could not fail to be attended with some
inconvenient effect ; but it remains none the less established
that all sickness (the mal des montagnes) disappeared, and that
the circulation returned to its normal rhythm under the
influence of one single inspiration of oxygen.

MM. Croce-Spinelli and Sivel, desirous of preparing
themselves for their high ascent of the 22nd March, experienced
analagous effects. I subjected them to a pressure of ll’8iix
M. Sivel, who was possessed of an excellent physique, was not
affected below lofin. M. Croce, of less robust constitution,
was very speedily attacked. At 1 l-8in. his lips were blue
and his ears nearly black : he was asphyxiated. Now,
one inspiration of oxygen alone caused in a moment all these
formidable symptoms to disappear. The pulse fell ; respiration
became free. At the moment when M. Croce became blind

AERONAUTICAL SOCIETY

oxygen suddenly restored him his sight. But they had, like
myself, experienced the impossibility of regularly breathing
pure oxygen. I therefore gave them to caiTy on their voyage
two mixtures of air and oxygen, the one contained 45 to 100
of carburetted gas, the other, 75 to 100, was reserved for
the greatest heights.

I will leave to the two intrepid aeronauts the honour of
exhibiting the important results of their successful ascent. I
will only add that without oxygen they would probably have
been unable to attain regions where they found again, with a
temperature of minus 7-6°, the ll-8in. of pressure which they had
supported in my apparatus. Without oxygen M. Sivel could
not have lifted the bags of ballast, nor M. Croce-Spinelli have
seen the lines of the spectrum he went on purpose to ob¬
serve. They breathed the mixtures without experiencing the
eblouissement.

I was desirous of testing upon myself the effect of the
continuous respiration of a sur-oxygenous mixture. In a first
experiment I was able, by employing a mixture of 45 to 100,
to lower with impunity the pressure to 13'3in., corresponding
to 17,S73ft., the height of Chimborazo. In a second, with a
mixture of 63 to 100, I descended to 9-84in., and I should
have gone lower still if my machine had been more powerful.
I only began to breathe oxygen after experiencing some incon¬
venience, and at the moment when my pulse had very
considerably augmented. From this moment all disagreeable
symptoms disappeared.

A sparrow I had placed beside me all but perished ; its
temperature having decreased from 41‘9° to 36T°. The
pressure to which I attained without sickness, thanks to
the oxygen, was that at -which Glaisher and Coxwell fell
insensible at the bottom of the car. It corresponds to the height
of the most elevated of mountain peaks, the Gaourichnika,

OF GBEAT BEIT ART.

which is henceforth theoretically accessible. I think it possible
in this manner to attain the pressure of 5'9in. Mr. Glaisher
was therefore right in saying — “ I have no doubt that obser¬
vations will ultimately be made in regions to which I have been
unable to attain without loss of consciousness. It is not for
me to take upon myself to determine the limit of human
activity.”

AERONAUTICAL SOCIETY

The following Paper, by M. A. Gaudin, was communicated
to the Societe Frangaise de Navigation Aerienne shortly after
the scientific ascent which preceded the late fatal balloon
accident : —

Upon the employment of Oxygen mixed with

Atmospheric Air in Respiration,
by

M. A. GAUDIN.

Translated by JAMES GLAISHEH, F.R.S.

Apropos of the very remarkable effects of the respiration
of atmospheric air enriched with oxygen confirmed by MM.
Oroce-Spinelli and Sivel during their last aerostatic ascent, I
remember to have obtained some long time since very analagous
results.

This was in the year 1832, on the occasion of the great
epidemic of cholera. A young physician employed me to
administer to the cholera-patients of the ambulance of the
Rue Grange-Bateliere pure oxygen to assist in producing
re-action. We operated upon the sick in the last stage of the
malady, and some were saved by the employment of this means.

M. Touzet immediately conceived the idea of creating an
establishment for breathing air enriched with oxygen, as a
preservative against cholera, and he confided to me its direction.

In the meantime the cholera disappeared, and only a few
solitary attempts were made by the aid of the apparatus I had
mounted.

OP GREAT BRITAIN.

M. Touzat prepared a mixture, consisting of equal parts of
atmospheric air, oxygen, and extract of the per-oxide of man¬
ganese, and caused some persons to inhale it, upon whom it
had the same effect as champagne.

For my own part, I tried the experiment, at various \ imes.
upon myself, by the aid of a suitably-arranged tube, and each
time I obtained an analagous result, that is to say, an extra¬
ordinary sense of freshness and relief which took from me all
desire to breathe again, so that on closing my mouth and
holding my nose I could remain for more than five minutes
without experiencing the least sensation of suffocation.

Nothing could be easier than to repeat this experiment, in
order to ascertain its entire bearing. It might furnish a very
important application for the service of divers employed in the
inspection and recovery of sunken vessels, and more especially
for fishers of sponges, corals, and pearls, if, by the aid of so
simple a means, we could triple and quadruple the duration of
time that a diver is able to remain under water.

AEBONAUTIOAIi SOCIETY

CONCLUDING REMARKS.

The preceding Papers contain information which would
otherwise have found a place in Concluding Remarks : these
will therefore be very brief.

The attention of Members is called to a Prize offered by
the Tayler Society at Harlem, “for a critical explanation of
what observation and theory have taught us concerning fly¬
ing, followed by the author’s researches, experimental and
theoretical.”

The Prize will consist of a Gold Medal, struck by the
Society, of the value of 400 florins.

The Papers must be written by another hand than that of
the author, and forwarded before the 1st of April, 1877, after
which date no further addition will be admitted.

The Prize for the best Essay will be declared before the
1st May following.

All the Papers sent in will remain the property of the
Society, who will insert in its publications, either with or with¬
out translation, the accepted Paper, the author renouncing all
right of publications except with the authority of the Society.
It also reserves the right to make such use as it may think
desirable of the unsuccessful Papers, either with or without
mentioning the name of the author ; but if the former, previous
consent will be sought. All Papers to be signed only by a
simple device, to be repeated in a sealed letter attached to the
Paper, which letter must also contain the name and address of
the author, the whole to be forwarded “A la Maison de la
Fondation de feu, N. P. Tayler, Van der Hulst a Harlem.”

OF GREAT BRITAIN.

An attempt was made by Mr. Simmons, the aeronaut, to
supplement the employment of a balloon in warfare by the
employment of a kite, which, from the peculiar nature of its
construction, he designated the parakite. It was, in fact, a
combination of the parachute and kite. It looked like an
enormous umbrella of loose cloth before inflation. When
distended by the wind, the upper wires — extending from the
central pole to the end of the diagonal bamboos — retained the
cloth in its place. On each side of those two diagonals, which
were at right angles to the direction of the wind, the cloth was
intentionally left in two loose folds, so as to leave an opening
for the compressed air to escape, on the principle of the Japanese
kite.

The theory was that the parakite would descend upon two
columns of air. This was so in practice, but there was a
difficulty in effecting its ascent. It was intended upon the
last occasion at Chatham, when under trial by the Royal
Engineers, to send up one of much smaller dimensions, and then
to attach the larger one, but the wind being boisterous and
gusty the larger one was fractured before ascent, so that the
smaller kite alone was experimented upon. The poles which
extended diagonally the square surface, were each 14ft. 6in. in
length. It rose to the height of about 200ft. To that height it
rose steadily with 601bs. of ballast, being double its own weight,
but refused to mount higher. On attaching another 60lbs.
it rose wildly and then swerved violently downwards, knocking
down a couple of boys and smashing itself. Repairs, however,
are easily effected with the aid of spare poles which run into
sockets.

The larger parakite extended about 700 square feet of light
waterproof material. The diagonal bamboos were each 30ft.
long, and the weight of all was 861bs.

It is to be regretted that on the several days appointed for

AgEONAUTIOAL SOCIETY

the experiments no trial could be made for want of wind,
except upon the last occasion, when there was a super¬
abundance. Such a machine requires a number of trained men
to manipulate it effectively, and just as they were becoming
acquainted with the required action the experiments ceased.
Mr. Simmons has since that time effected improvements

in it.

The Californian flying machine again crops up during the
past year. The sustaining power of gas, which was depended
upon to help in part the action of the extended planes when
propelled against the air, has been quite abandoned, and the
machine now consists wholly of plane surface, steam engine,
and screw propellers. Instead of the planes being extended
laterally, however (for there are three), they are superposed
longitudinally, with an interval of about 10ft. In length the
whole structure is 120ft., fixed upon a foundation of trussed
bamboo. The planes are unequal in length, the largest on the
top being of the above dimensions and about 40ft. wide.

These three planes are rigidly supported by two masts
about 40ft. high, and stayed by wire rigging.

To the lower end of each mast is affixed a small wheel, to
run down an inclined single rail, so as to impart the necessary
initial velocity. This is then to be continued by means of an
engine enclosed in a square compartment, capable of holding
the engineers. This compartment is fixed in the centre of the
trussed bamboo keel. The engine works four screw-propellers,
two vertical and two horizontal. Their place of working
breaks the continuity of the longitudinal planes.

The weight of the whole machine is calculated to be
l,5001bs., this is inclusive of man and motive power, &c.

It was to have been tried in November last, but we have
not received further particulars.

or QBE AT BBITAIN.

At the General Meeting of the Societe Franqaise de
N avigation Aerienne,held on the 3 rd December, 187 5 — President,
M. Paul Bert, Professor a la Faculte des Sciences — M. le Docteur
de Villeneuve. the Secretary General made the following observa¬
tions : —

“ Our Society is not the only one which occupies itself in
the study of Aerial Navigation. The Aeronautical Society of
Great Britain has been founded these ten years by Mr. Fred.
W. Brearey, who performs the duties of Honorary Secretary, a
position corresponding to that of Secretary General with us.”

After passing some complimentary observations upon
Mr. Brearey’s exertions in the cause, he said —

“The French Society thought it only justice to show its
appreciation of his services by awarding him its Gold Medal.
Mr. Willoughby, the English Vice-Consul, acknowledged the
compliment paid to his countryman, and undertook to hand it
over to Lord Lyons for transmission to the Duke of Argyll, the
President of the English Society, who, at his Grace’s residence,
delivered the same to Mr. Brearey.”

In the completion of this, the Tenth Annual Report, we
may look back with some amount of satisfaction at the gradual
retirement of some of the imaginary obstacles which puzzled
and bewildered the earnest inquirer into the principles of
flight. The readers of our Reports cannot but be impressed
with this truth. In applying the knowledge thus attained to
the accomplishment of flight, mechanical difficulties have yet
to be surmounted. Expensive failures are aiding in this object.

It cannot now be said that the want of a light motive
power presents any difficulty.

It has often been asked if the Society offers any prize for
the successful achievement of flight by man ? The answer
ought to be obvious — that no amount of money which could

AERONAUTICAL SOCIETY

be offered by the Society would adequately reward success.
The remuneration must be looked for, and would doubtless be
realized, through other sources.

It might, however, be a question whether the Society
should, by the aid of its Members, offer prizes for models which
shall be capable of imitating the flight of selected specimens in
nature, such for instance as the stag-beetle, the butterfly, the
dragon fly, the hovering of the hawk, or the flight of the
swallow.

Some very effective models have been constructed by
MM. De Villeneuve and Penaud of the French Society. They
are very light and somewhat evanescent in the duration of flight,
but certain conditions, as to weight-carrying capacity, might be
attached independently of size, and they should be capable of
flying a certain distance independently of time. It must be
observed that no open air demonstration is feasible, as an
apparatus of some weight can alone contend with the ground
currents. A large space like the Central Hall at the Alexandra
Palace would suffice for every condition. We leave this sug¬
gestion to fructify with such of our Members who may approve
of the suggestion, and can aid in contributing to a handsome
prize for so interesting an exhibition.

OF GBEAT BEIT AIN.

MEMBERS.

Alexander, A., M.A., C.E., Cyclops Steel and Iron Works, Sheffield ;
of the Council.

Anderson, Capt. A. Dunlop, 23rd Punjab Pioneers, 21, Lennox Street,
Edinburgh

Arbuthnot, H. Gough, 40, Prince’s Gate, s.w.

Argyll, the Duke of, F.R.S. ; President of the Council

Armour, James, C.E., Gateshead

Ashbury, James, M.P., 66, Grosvenor Square, w.

Ballard, Stephen, C.E., Colwall, Great Malvern
Barber, William, 9, "The Boltons,” Kensington, w.

Baring, Colonel, 36, Wilton Place, s.w.

Barnett, E. W., 25, Lancaster Gate, w.

Barrett, Frederick, Langley House, Grove Lane, Camberwell, s.e.
Baxter, Richard, F.R.G.S., 19, Leinster Gardens, w.

Beadon, Captain R.N., Creechbarrow, Taunton
Bell, Charles W., Roche Court, near Salisbury
Bennett, T. J., 20, Little Clarendon Street, Oxford
Biddle, Dr., Kingston-on-Thames
Bobthwicjk, Lord, 35, Hertford Street, May Fair
Bourne, John Fred., C.E., Louth, and Civil Service Club
Bourne, Mrs., Hilderstone Hall, Stone, Staffordshire {Associate)
Brearey, Fred. W., Maidenstone Hill, Blackheath ; of the Council, and
Honorary Secretary.

Bright, Sir Charles Tiltston, F.R.A.S., 26, Duke Street, Westminster,
s.w. ; of the Council

Brooke, Charles, M.A., F.R.S., 16, Fitzroy Square ; of the Council
Brooks, Maurice, 10, York Terrace, Regent’s Park
Brown, Davld Stephens, Braywick House, Green Lanes, Stoke
Newington

-iftRONAUTIOAL SOCIETY

Browning, John, F.R.A.S., 63, Strand; of the Council
Bhunton, N.W., 116, Belsize Park Gardena, N.w.

Burnaby, Captain, Royal Horse Guards ; of the Council
Burrell, Edward, The Hermitage, 7, Melina Place, St. John’s Wood
Burton, Rev. Roger Taylor, M. A., TheVicarage, Great Tey, Kelvedon,
Essex

Chaplin, James C., 1 2, Craven Hill, Hyde Park
Chatto, Andrew, 74, Piccadilly
Childs, Thomas, Beaufort House, Ham

Clare, Walter F., Engineer, 2, Agnes Cottages, Elm Grove,
Hammersmith

Crest adoro, Dr., Free Libraries, Manchester

Crosland, J. M., Holly Lodge, Thistle Grove, South Kensington

Davies, Charles, 47, Pall Mall

Dawson, G. J. Crosbie, C.E!, Rowley Park, Stafford

Deck, Arthur, King’s Parade, Cambridge

Decruz, E., Seetarampore Colleries, Raneegunge, Lower Bengal, India
Delane, John T.. 16, Sergeant’s Inn, Fleet Street
De Satrustequi, Don Joaquin Marcos, Consul General de Espafia,
21, Billiter Street

De Villenkuve, Dr., Rue Lafayette 90, Paris

Diamond, Hugh W., M.D., F.S.A., Twickenham House ; of the Council
Dupferin, Earl of, 8, Grosvenor Square ; Vice-President of the Council
Ellis, James, 337, Strand, w.c.

Elphinstone, Lord, 24, Carlton House Terrace
Emden, Walter, 76, Russell Square

Frost, Edward P., J.P., West Wratling Hall, Linton, Cambridgeshire
Ganthony, Richard, Eton Lodge, Richmond
Glaisher, James, F.R.S., F.R.A.S., &c., Blackheath ; of the Council
Gordon, R. Newton, I, Blomfield Road, w.

Greenfield, Capt. J. Tyndall, R. A., Stanton Harcourt, Upper Norwood
Greetham, Thomas, 26, Bedford Row, w.c.

Grosvenor, Lord Richard, M.P., F.R.G.S., 76, Brook Street, w. ;
Vice-President of the Council

Hall, Alexander Lyons, F.R.G.S., 48, Blenheim Crescent, Netting Hill

OF GREAT BRITAIN.

Halt., George Samuel, Saville House, Billingshurst, Sussex
Harrison, A. Stewart, 133, Upper Thames Street
Harper, J. E., 257, Southampton Street, Camberwell
Harte, Richard, 2, Devonshire Terrace, Notting Hill Gate
Hat, Rear-Admiral Lord John, 149, Piccadilly ; of the Council
Holland, Robert, Stanmore, Middlesex
Hudson, C. Donaldson, 51, South Audley Street
Jay, R. C., 54, Alexandra Road, Cambridge Gardens, Kilburn, w,
Jennings, William, F.R.G.S., 13, Victoria Street
Knight, John, Oakhill, Hildenboro, Kent
Krueger, W. G., Downeville, Sierra County, California
Latham, Baldwin, C.E., 7, Westminster Chambers
Le Feuvre, Wm. H., C.R, F. R.G.S., St. Antholin's Chambera,
26, Budge Row, Cannon Street, E.C. ; of the Council
Lilienthall, Otto, Albrecht St. 13, Berlin
Lindsay, Lord, 47, Brook Street, w.

Londonderry, the Marquis of, Londonderry House, Park Lane
Longridge, James, A., C.E., 3, Westminster Chambers
Ludeke, J. Ernest F., 15, Wilmot Place, w.

Macdonald, Colonel, 27, Park Lane, w.

Manners, Lord John T., Guards’ Club, fi.w.

Marriott, Frederick, San Francisco, California
Matthews, Edwin, 26, Bedford Row, w.c.

Maxwell, Captain R. J., Army and Navy Club, s.w.

Michaels, J. Porter, Chiistinen Gasse, No. 4, Kolowratring, Vienna

Morrieson, Colonel R., Oriental Club

Moy, Thomas, 37, Farringdon Street

Mulliner, F., 59, Great Charlotte Street, Liverpool

N ees, Christopher, Telegraph Director, Elsinore, Denmark

Newman, Frederick, C.E., 51, Belsize Road

Ofenheim, Victor R. Von, Schwarzenberg Strasse 18, Vienna

Ohren, Magnus, A.I.C.E., F.C.S., Lower Sydenham ; of the Council

Osler, Abraham Follett, F.R.S., Birmingham

Owen, Captain R.A., 43, The Common, Woolwich

Penaud, Alphonse, 14, Rue Castellane, Paris

AERONAUTICAL SOCIETY

Perigal, Henry, Jun., 9, North Crescent, Bedford Square
Phillips, W. H., Cemetery Road, Nunhead
Risley, J. B., C.E., Brondeg, Ferry side, South Wales
Roberts, Major H. C., 48, Hereford Road, Bayswater
Sknecal, P., 96, High Street, Kensington

Siemens, C. W., C.E., F.R.S., 12, Queen Anne’s Gate, Westminister
Stringfellow, John, Chard, Somerset
Sutherland, the Duke of ; Vice-President of the Council
Thorman, A. J., 281, New Cross Road, s.E.

Tolme, J. H., C.E., 9, Victoria Street, Westminster
Tracy, The Honourable Henry Hanbury, Gregynog Newton, Mont¬
gomeryshire

Walker, Charles Clement, Lilleshall Old Hall, Salop
Walker, Thomas, 24, Oxford Street, Birmingham
WENHAM, F.H., C.E., V.P.R.M.S., Padnall Hall, Chadwell, Essex ; of
the Council

Wilson, George, 7, Church Terrace, Union Grove, Clapham
Wright, Henry, Stafford House, St. James’ ; of the Council
Yorke, Pierce Wynne, Dyffryn Aled, Abergele

OF GREAT BRITAIN.

PRESENTED BY THE COMMISSIONERS

THE FOLLOWING

SPECIFICATIONS OF PATENTS.

Subject. Patentee.

Improved Apparatus for Navi- j john O’Connell Cave,
gating the Atmosphere . J

An Improved Kite or Aerial \

Apparatus for Military and f ^ ^ ^
other purposes (Communicated t
by F. C. U. P. d’Esterno) ... )

Improvements in purifying gas, 'j
the means and Apparatus for j
inflating and rendering ascen- ! J. Simmons,
sive Balloons and other Aerial f J. M. Morris.
Machines, and in the Appara- j

tus employed therein . )

Improvements in the Means'
and Apparatus for generating
fluid to work Engines so as to
develope great power in pro- j- M. P. W. Boulton,
portion to bulk and weight, I
more particularly applicable to
Aerial Locomotion

1690 May 6. Apparatus or Means
pelling and Steering

2428

July 5.

Improved Means and Apparatus j
f or c< i n vey i n g or carry i ngh u m an
beings or objects into mid-air ]

> J. Simmons.

2901

Aug. 17.

Improved Method of, and Appa-
tus for, Steering Balloons ... ;

j D. Biddle.

2979

Aug. 25.

Balloons .

H. McKee.

3315

Sep. 22.

Improvements in the Naviga- ’
tion of the Air and in Appara- (
tus therefore (communicated (
by E. Vidat) . ,

► P. Jenson.

8369

Sep. 22.

An improved Aerial Vessel for 1
Maritime and Fluvial Navi- (
gation (communicated by i
B. Picard and A. Lawrent) . . . J

A. C. Henderson.

4151

Dec. 2.

A new Flying Machine .

J. K. Smythies.

for Pro-
Balloons

J. S. A. Menier.

No. Pate.
1875.

140 Jan. 14.
169 Jan. 15.

289 Jan. 23.

694 Feb. 17.

AERONAUTICAL SOCIETY

BOOKS, PAMPHLETS, &c„ BECEIVED.

Memoir sur la Navigation ACrien ne, par M. Menier. — By the Author.

Smithsonian Reports for 1873-4. — Presented by the Smithsonian Institu¬
tion, Washington.

Rivista Dcyli Studi di Locomozione e Nautica nell' aria Di P Cordenons,
Prof, di Matcmatica nel R. Liceo di Rovigo. — By the Author.

Aviation — Apparcils de Vol Mtchanique, par M. A. Pinaud — By the
Author.

Navigation A Criennc Serieuse, par Vaussin Chardanne IngSnieur Civil —
By the Author.

L' A&ronaute, Monthly Eeports of the “ SocietS Frangaise de Navigation
Airienne."

Projet d'un ASrostat prapre a la Ndvi/ Uinn A&rienne suivi dun projet
d Aerostat — Obscrvatoire pour le service des Armies en Camp ague, par
C. Ficss— By the Author.

Ro. >k I i

dlefontfi §,nratal lupor*

or the

AERONAUTICAL SOCIETY

GREAT BRITAIN.

FOR THE YEAR 1870.

PRINTED BY

HENRY S. RICHARDSON,

GREENWICH.

Reprixlared mid printed photo! it ho off eel for
Peter Murray Hill (Publishers) Ltd.

73 sloank Avenue
London s.W.3
1 056

/{// pcrmiexinn of the Royal Aeronautical Society

M \ I > k
I*.

AND I'MNTKD IN DllKXT HlilTAlN II V
li. Hill. MAN A '«»NS I. ID. KIluMK

THE

AERONAUTICAL SOCIETY OF GREAT BRITAIN

Prestbent,

HIS GRACE THE DUKE OF ARGYLL, K.T.

Uke^Preatbent,

HIS GRACE THE DUKE OF SUTHERLAND.
RTGHT HON. THE EARL OF DUFFERIN.

LORD RICHARD GROSYENOR, M.P.

f^onararg Secrctarg,

FRED. W. BREAREY, Esq.

porter arg Sol fri tors,

Messrs. MATTHEWS & GREETHAM, 26, Bedford Row.

Coundl,

A. ALEXANDER, Esq., C.E., M.A., Sheffield.

FRED. W. BREAREY, Esq., IMaidenstone Hill, BUckheath.

Sir CHAS. T. BRIGHT, F. R.A.S., 26, Duke Street, Westminster
CHARLES BROOKE, Esq., M.A., F.R.S., 16, Fitzroy Square.

JOHN BROWNING, Esq., F.R.A.S., F.R.M.S., 111, Minories, and
63, Strand.

Captain BURNABY, Royal Horse Guards.

JAMES GLAISHER, Esq., F.R.S., F.R.A.S., Blackheath.
Rear-Admiral Lord JOHN HAY, C.B., 149, Piccadilly
W. H. LE FEUVRE, Esq., C.E., F.R.G.S., 28, Brunswick Gardens, w
Lord LINDSAY, F.R.A.S., 47, Brook Street.

MAGNUS OH REN, Esq., A.I.C.E., F.R.S., Lower Sydenham.

F. H. WENHAM, Esq., C.E., V.P.R.M.S., Padnall Hall, Chadw ll.
Essex.

HENRY WRIGHT, Esq., Stafford House, St. James'.

WITH POWER TO ADD TO THEIR NUMBER.

Member’s Subscription, £1. Is. per annum, dating from the day of Election.
Ladies may become Associates upon the same terms.

<&Iebmfjj Annual ^tyott

OF THE

AERONAUTICAL SOCIETY OF GREAT BRITAIN,

FOE THE YEAE 1876.

Containing an Account of the Proceedings and a Selection from the
Papers and Communications received by the Society during the
year, with Concluding Remarks upon the present state of the
Science.

The Annual Meeting of Members of this Society was
held in the Booms of the Society of Arts, Adelphi, on
Wednesday Evening, the 7th June, 1876, at Eight o'clock, for
the reading and discussion of Papers and the general advance¬
ment of the Society’s interests. Mr. Chaeles Bbooke, F.E.S.,
was called upon to take the Chair.

The Minutes, having been previously approved at a
Meeting of the Council, were taken as read.

The Chaibman called on Mr. D. S. Brown, who read his
Paper on

THE ADVANTAGES OF EMPLOYING POWER FOE
AERIAL PROPULSION in an INTERMITTENT MANNER,
AND ON THE SOARING OF BIRDS.

I have before directed attention to the advantages of
employing power in an intermittent manner, and at the General

AERONAUTICAL SOCIETY

Meeting of the Society in May, 1874, I gave a practical illus¬
tration of it. I have now to submit a modification of the
principle, which I believe to be well adapted for aerial propulsion.
Suppose that the rods or poles connecting the planes of the
bi-plane, which I then described, to be substituted for a tube,
the tube also to serve as the cylinder of an engine, to be worked
by the explosion, at short intervals, of petroleum gas, giving
motion to a piston having a parachute propeller fixed to the
outer end of the piston-rod, so as to act directly on the air by
expanding as it is driven one way and collapsing when drawn
the other. By this means it is probable a sufficient velocity
can be attained, which I fear will be difficult if not impossible
to accomplish by any rotary propeller.

I have also lately devoted some attention to the soaring
of birds, with a view as to the direction in which our first experi¬
ments in flight on a large scale should be made, and for which
the bi-plane, on account of its great stability and the facility
which it affords for balancing, is well adapted. I should state
that when the planes are rigid and not inclined, and the centre
of gravity is midway between them, it will neither pitch nor
skim, but assume a horizontal position when not propelled, and
so fall gently to the ground. But if the weight be at the
extremities or moved somewhat forward, and the bi-plane be at
the same time inclined, it will then glide downwards with great
rapidity by the force of gravity alone, on account of the oblique
manner in which its under surface encounters the air. If, again,
it be supposed to carry a man, he could give to it the required
direction, bring it afterwards gradually into a horizontal
position, and finish by inclining it upwards, by which the
whole momentum of the machine would be brought to act on
the air, and it would then probably reach nearly the same
elevation as that from which it descended, besides having made
some progress forward. But to obtain the greatest extent of

OF GREAT BRITAIN.

progressive motion the horizontal position should be maintained
as long as possible, and the velocity increased when required
by making another dip downwards. Supposing the weight of
the machine and man to be 3001bs., and to be launched into
the air at an elevation of 1000ft., there would thus be
developed from gravity alone a force equal to one horse during
the descent, provided it were made in ten minutes, or ten-horse
power if made in one minute. Here, then, is ample force to
commence with — one that weighs nothing or costs nothing.
The bi-plane could be elevated to the required height by giving
to it a rapid horizontal motion, which could be done gradually
with a rope and windlass, and the horizontal motion afterwards
changed to one inclining upwards ; or it could be elevated in a
breeze, like a kite, and released from the rope when a sufficient
height had been attained. I think, however, that soaring birds
are greatly aided by the unequal or constantly varying velocity
with which the wind blows, because if the line a be supposed

to be the plane of a bird soaring, say at an angle represented
by a rise of 1 in ten, and with the wind blowing from b to c,
it is evident that any sudden gust would have the effect of
lifting it upwards with a force ten times as great as it would
drive it backwards, and the consequent increase in elevation
would be so much power gained, which the bird would not fail
to turn to the best account, after reaching its maximum height,
by gliding down again when the gust was over and using its
falling weight instead of muscular power to regain its forward
position. On the other hand, if the velocity of the wind were
quite uniform it would soon impart its complete motion to the
bird, and the two would then form one moving mass.

Sir George Cayley thought that the soaring of birds is

AEBONAUTICAL SOCIETY

due to the upward currents of air reflected from cliffs, hills, &c.
That such currents exist to some extent there can be no doubt,
although I have never heard of their effects having been felt
by aeronauts in the descent of parachutes on a large scale,
although pieces of paper and other light substances are often
lifted and borne away by them, or at least by some whirling
or other motion of th® air, and in rare instances heavy bodies
as well. It is possible that the direction of the wind may not
always be quite horizontal but slightly inclined upwards, in
which case there would be no necessity for any inclination in
the body of the bird. By experimenting with the bi-plane
in soaring the art of aerial balancing would be acquired, which
is very important. But it will doubtless be asked, can it be
made large enough to carry a man and yet weigh no more in
proportion to its surface than a light bird, say about lib. to
every square foot of surface. My opinion is that it can, although
there are some circumstances that tell against that opinion and
some for it. I will state them very briefly. The weight of any
framework, when the same proportions are adhered to, increases
according to the cube of its dimensions, and the strain upon it
in the same ratio as the dimensions, so that by simply augmenting
the lines of a structure ten times we increase its weight a
thousand times, and it would also be, when so augmented,
relatively only one-tenth as strong. On the side of gain, how¬
ever, there are the following facts. The surface of an aeroplane
increases according to the square of its dimensions, but
practically the sustaining power is more, for, according to
Hutton, large surfaces resist the air more in proportion than
small ones, so that by increasing the dimensions ten times we
increase the sustaining power considerably more than a hundred
times ; and as regard the framework, it is more easy on a large
scale to avail ourselves of those -esources which exist for
strengthening it than it is on a small one, such as by making
it tubular or oella-tubular, Sec.

OP GREAT BRITAIN.

In conclusion, I have only to state again that all experi¬
ments involving human or other life should, for greater safety,
be made over water.

At the conclusion of the Paper

The Chairman said the Author had directed their
attention to the subject generally, and they would now be
glad to hear any remarks.

Mr. Senkcal observed that it was of great importance
that aerial apparatus should be able to come down vertically
and gently, otherwise a model, going at some velocity, instead
of coming down in one corner of the room might come down
in another.

Mr. Bbown : The velocity can be instantly stopped by
giving an angle up. If a bird wishes to stop he gives a little
angle up and stops instantly. One plane is before the other :
they are not side by side.

Mr. SIsnecal : It is important to attend to the point of
safety in coming down.

A Paper by Mr. Armour, C.E., on “Air Compression
under Wing-planes,” was read by Mr. F. W. Brearey, the
Secretary of the Society, who stated that the Author was
prevented from being present at the Meeting by an engagement
at Newcastle-upon-Tyne.

AIR COMPRESSION UNDER WING-PLANES,

Within itself, when unresisted, the air in motion in a
passing wind is of the same density as neighbouring air at rest.
In gusty weather, when smoke or vapour is in the air to reveal
the motion, we can see that, though making quick whirling
changes, the air ever moves in buoyant bulk ; and, neglecting
the elastic pressure that must occur between two whirling

AERONAUTICAL SOCIETY

volumes that blend together with unequal motion, the vapour
forms, however ragged and shredded out, show no indications
of varying density anywhere, for the lightness and elastic
buoyancy and freedom is uniform throughout, and the ragged
vapour forms and the clear air between are carried by the
eddies equally.

This uniformity of density, however, is at once broken
when a wing-plane is presented to the current. Against the
windward face the air compresses itself by the force of its
momentum, and thereby forms a cushion of resistance. In the
time of the compression the weight of air compressed has
expended its motive force, and the force of the impact, whether
derived from air thus in motion against the wing, or from the
wing beating against still air, determines the value of the
support that the wing receives.

The normal pressure of the atmosphere is 151bs. per
square inch nearly. The mechanical pressure of lib. per
square foot of wing-plane is only about 00071b. per square inch,
or about l-2140th of the normal pressure; and as the elastic
pressure of air is according to the density, the air come upon
by the wing-plane would give the required static resistance of
lib. per square foot to the passing body, if enduring compression
to the extent of l-2140th of its normal volume.

The air under a bird’s wing, however, being free for
displacement on all sides, we cannot argue for it as in the case
of air enclosed, and are at present unable to determine the
depth of volume that would be active in resisting the displacing
pressure in the time the plane would be in contact, and are
free to reason only that the pressure is made sensible simply
by the resistance offered by the inertia of the air beneath it,
and that this force of air-inertia is equal to that of the weight
of pressure in the plane.

The form of the wing, however, with its lateral extension

OF GREAT BRITAIN.

and its forward motion in flight, allows to the air come upon
only the downward direction for the motion of displacement
during the short time of contact; and in the elasticity and
ready compressibility of the air do we look for tlje com¬
pression needed for the support of the passing weight, and
believe that this compression must be experienced by the air in
immediate contact with the plane, in the act of transmitting
the pressure to the outlying weight of air ;• and we consider,
further, that the quicker the velocity of the plane the more
compact will be the volume of compression.

Thibault, experimenting with forms square, circular, and
triangular, propelled with their faces perpendicular to the
direction of the motion, so that the whole area was pressed
equally, found the resistances were independent of the form he
had given to the area. In the question of mechanical flight,
however, we have to deal with angular pressure, in which it is
evident that the forward and the rearward surfaces are acting
under different conditions on the air.

The value of the sensible pressure for the sustenance of
free weight cannot be estimated irrespective of the time
occupied in its development upon the air. In the case of any
given force of inertia developed in air, and in sustaining balance
with the imposed pressure, any slight addition to this imposed
pressure, requiring corresponding increase in the sustaining
force of inertia, acts as free or unbalanced motive force until
the additional resistance needed for its sustenance is developed
in the air.

Fig. 1.

In Fig. 1 let ab represent a plane measuring X foot square.

A&tONAUTICAIi SOCIETY

and the forepart of it, ax, the 3 inches breadth of a narrow
plane, with motion in the direction of the arrow.

The plane must travel a certain distance cd, in imparting
the motion of compression ad, and in travelling further, say
the distance ce, we may regard the surface volume acef as
receiving the motion of direct compression ; and aB it is clear
that the act of direct compression by the plane, ends when the
sustaining density has been reached, we have this compressed
air interposing in the manner of an elastic cushion between the
plane and the body of air beneath, so that the body of air
beneath can receive displacing pressure through the cushion
only, the density of the cushion not being increased by this
duty, but may rather be diminished, because, in the time dh
the pressure is tending to put the bulk of free air beneath in
motion bodily, the rearward area cb seemingly acting mainly as
an abutment to the elastic cushion pressure, which is thus
acting freely outwards upon the air beneath, say on the short
line dh, while the plane is advancing on the longer line bk.

If ah were air come upon at rest in a confined space, and
suddenly compressed to the extent ad, the sum of the dynamic
energy that would be expended in, the act, first, of compression
to the required density, and then, at the point d, of starting
the compressed weight at the velocity of displacement
assumed for the plane in constant motion, would amount to
more than the weight of the quiet force that would be sufficient
to maintain the compression at the point d, but the difference
in the greater amount would have expression in the motion of
displacement of the air beneath ; and if this quiet force
be represented by the pressure due to the density of the cushion
of compression, we have in the cushion acef work equal to the
dynamic energy expended in the compression, acting uniformly
through the time ce ; and in the volume cbge the elastic
pressure due to the density of the compression maintained

OP GBBAT BEIT AHf.

by the continued advance of the plane, but doing work in the
displacement of the bulk of yielding air.

The surface volume of compression acef is seen in Fig. 1
to be common to the two planes ax and ab, but experimental
data is yet needed to determine the rate at which the expansive
pressure of the cushion diffuses itself with displacing force
through the bulk of free air beneath ; and, likewise, the
limit to which, with a given velocity and angle of inclination,
the narrowing of the wing-plane may be carried without loss
of effect.

The depth, as shown in Fig. 1, for the volume, of com¬
pression is purely arbitrary.

Fig. 2.

t t

In Fig. 2 let a, b, c, d, and e represent five distinct volumes
of air at normal density, that may be acted upon in successive
order and together. First, compress a and b into the single
volume b and call the double density 1. Next, let this double
density relieve itself by thinning into the successive volumes
c, d, and e. We will thereby have the ratio of volume to the

AERONAUTICAL SOCIETY

original double density 1, in these successive enlargements of
volume, in the order,

b c d e

0-5. 0-66. 0-75. 0-80.

Now, assuming these ratios of varying density in suc¬
cessive strata to occur in the cushion and the body of air
immediately beneath, at some point below d, Fig. 1, with the
greater density b in contact with the plane, we would have the
force of inertia in the successive strata developing with the ve¬
locity in prdportion to the displacing wave pressure that decreases
outwards towards e in the yielding body of air, and would have
a wave of pressure e keeping, roughly speaking, about the same
relative distance in advance of b in the transmission of the
pressure through the body of air that has to be put in motion ;
but as the density of c, with its less fully developed force of
inertia, is only about O' 75 the density of b, the tendency here
would be for b, with its maximum expansive force, to expand
into c in advance of the motion given by the plane, and
similarly with regard to the other volumes d and e.

We would thereby have the density next the plane, say at
some point, i. Fig. 1, thinned to less than the density that
obtained when the force of inertia of the weight of pressure
was started with the given constant velocity at d : that is, the
pressure b of Fig. 2 would be partially converted into motion
in c, while the more distant effect in e would be modified by
the loosening of the air about the rear of the plane.

The work done through the cushion can be no greater in
amount than the work thrown into it by the plane, but the
act of compression and the starting into bodily motion of the com¬
pressed volume of resistance near the forward edge, before the
imposed pressure has been transmitted far enough to put the bulk
of air beneath in motion, gives to the forward area of the plane
more duty to perform than is done by the rearward area, which

OF GBEAT BEIT AIN.

comes upon air that is already started, so that the work to be
done by the rearward area upon the body of air already yielding
beneath is, in amount, only the difference between the force of
resistance already developed in the yielding body by the forward
area and the displacing force.

In a stationary stroke, say of the wing of a bird that does
not leave its perch, resistance is developed on a surface of air
equal simply to the area of the wing ; whereas, in flight,
resistance is developed on an extended surface equal to the
length of wing from shoulder to tip by the distance travelled
in a given time.

In the stationary stroke we have the wing-pressure main*
taining, in continuous manner, the definite wave of displacing-
pressure, which was originated and put in motion by a definite
effort, say at the beginning of the stroke ; whereas, in the
stroke made by the same wing during flight, though the
constant area of resistance be the same as in the stationary
stroke, the wing in a given time has had to expend force in
developing a wave of pressure from an extended surface area
equal to the space that the wing has travelled over in that
time, the energy and weight of the respective stationary and
flight waves being determined by the velocity of the respective
strokes.

In the formation of the cushion of resistance in new air, with
the wing coming with sustained constant velocity upon air as¬
sumed to be at rest, we have the resistance of the air’s expansive
force developing with the growing density under the mechanically-
applied compressive force of the wing, and the suddenness with
which the force acts, confines the direct effect of the impact to
the air more immediately in contact with the wing face ; but,
simultaneously with the motion of compression that forms the
cushion of resistance on the front face of the wing, we have
displacement motion developing in the rear, the air there

AERONAUTICAL BOCTETY

moving, say, laterally inward behind upon the wing, the cushion
of resistance when formed acting upon the body of air beneath
it in front and displacing it, say, laterally outwards to take, it
may be, in the case of the stationary stroke, the place of the
air that is thus closing in behind ; and as all this lateral move¬
ment in both front and rear is produced by the action of the
wing, and as the lateral motion is motion of displacement due
to the action of the wing, we have, once the cushion of resistance
is formed and in motion, the displacement-resistance represented
by the sensible pressure due to the density of the air that forms
the cushion.

In the case of a wing in flight, however, the lateral motion
of displacement outward from the front face and inward upon the
rear face will not occur in the balanced manner we have spoken
of with more immediate reference to a stationary stroke, or to a
plane falling vertically, as the air displaced from the front face
of the wing in flight gets clear only when the wing has passed
beyond. Moreover, any tendency to a partial vacuum on the
rear face of the wing would cause the wing to flatten to the
direction of flight under the sustaining pressure developed on
the under face.

To produce the up-and-down motions of a wing stroke it
has been suggested to rotate the wing-planes round a horizontal
axis. This would give velocity of rise equal to the velocity of
fall; whereas, in bird flight, according to Marey, the rise is
quicker than the fall.

In the case of a bird, however, the rise and fall occur
alternately, whereas, in a rotating series of planes rise and fall
occur together in continuous action.

OF GREAT BRITAIN.

Fig. S.

In Fig. 3 let a and b be two wing-planes rotating round
the axis A, in the direction indicated by the arrow i.

It is apparent that if the centre A be stationary the
downward resistance get will be in balance with the upward
resistance hb, when the planes are in the relative positions
shown, and the motive power exerted through the axle A will

AEBONAUTICAIi SOCIETY

have to overcome resistance ga + hb, with leverage A a, and
the gravity of the dead weight will be unsupported.

If motion of translation, however, be given to the centre A,
in the direction of the arrow j, we then have the wing-planes
a and b moving in a curved path indicated by the curved
arrows cd and ef, with the resistances perpendicular to the face
of plane roughly indicated by the arrows k and l, both acting
in the support of the dead weight, while the motive power
exerted through the axle A will have to overcome only
the angular resistance to progression due to the angle of
inclination on the path nad or rnbf.

The difference between these two angles as drawn in
Fig. 3, however, in relation to the horizontal line j, gives to k
a backward tendency similar to the tendency in a bird’s wing
when rising.

This, as in the case of the bird, will act in slowing the
velocity of translation j, and thereby will increase the angle of
inclination of the curved path at a and b ; but as the velocity
of rotation, i, is assumed to continue constant, and as the plane
will not be free to oscillate farther than shown at b, we have
on the shortened path j, and consequent greater angle rnbf the
plane b exerting maximum lifting or sustaining pressure, while
the plane at a , being free to oscillate at the angle shown, is
rising with a flatter angle nad; and as we assume the rear
edge to be elastic, it is evident that the rearward curve at b
will act in favour of the velocity of translation j.

Each wing-plane, in rotating order, will form a surface of
resistance for itself in advance of the one preceding, the
distance in advance being determined by the velocities i and j.

If the velocities i and j are equal, as in the case of a wheel
running on the ground, then the wing-plane, gradually slowing
on the path vo, is for the moment stationary at the lowest
point o, the loss here, however, being recovered at the highest

OF GREAT BRITAIN.

point of rotation r, where the wing-plane, with flattened angle
of inclination xrt, is in motion with velocity i + j.

When the motion j is in excess of the motion i we will
then have the plane descending on the curve yo and rising
on oz.

The spindles on which the wing-planes oscillate in assuming
the required angles of inclination are supposed to be kept by
mechanical means in connection with the axis A, so that the
wing-planes balanced on them shall always have the same edge
leading, and to allow of the oscillation the wing-plane may be
not keyed to the spindle, but connected to it by a light spring,
which may be, say, of spiral form, concentric with the spindle,
and which, when the wheel is at rest, would keep the wing-plane
uniformly at the easy angle shown at the lowest point o.

The rearward part of the plane op would here require to
be slightly greater than the forward part og, but the plane
would be so set on the spindle, that when at the point b the
excess area of op would be greater than when at the point a,
so as thereby to neutralize the greater effort of the restraining
spring at b.

On a former occasion, when the forces at work were more
imperfectly comprehended than now, we spoke of planes rotating
in a wh^cl that made its starting run upon the ground ; but,
to get the required starting pressure on them to give sustenance
to the weight that will have to be carried, their motion of
rotation at the first will have to be quicker than running
contact with the ground would admit of : better to launch out
as a bird does from a perch.

Further, two systems of wing-planes in wheel form, one
placed in advance of the other with the weights and motive
power seated between them, would certainly be found preferable
to a single wheel with the load within it.

AERONAUTICAL SOCIETY

After the reading of the above

Mr. Moy said that he thought that it was due to the
Society that any Gentleman sending a Paper of this description
should send also a model to explain its action. The action of
the proposed plan was somewhat like a paddle-wheel of a
steanci vessel, with floats of a wave-form intended to act upwards
both in the downward and upward motion. With respect to
the wave-form of aeroplane he believed he was the first to
propose that form. In doing so he had drawn his conclusions
from ship building experience ; but he had since then modified
his tiews, as ships had to provide for the closing in of the water
at the stem after moving the water laterally. But the wave-
formed aeroplane might well be cut in half, leaving the air in
motion to take care of itself instead of providing for bringing
it again to a state of rest. But as such coarse angles as those
shown in the drawings were quite out of the question> and very
fine angles must be used, the flatter the aeroplanes were made
the better.

Mr. Bee abet : After what has been said about inclined
planes I am plainly inclined to bay they should be quite flat.
(A laugh.)

Experiments Were made in the room with a small aeroplane
set in motion by Mr. Brearey, who introduced to the Meeting
Mr. Cayley- Worsley, nephew of Sir George Cayley, whose
experiments in aeronautics were well-known to most of the
Members.

Mr. S^nEcal enquired if there were any data on that
class of experiments ?

Mr. Brearey: Yes; you will find it all in “Nicholson’s
Journal.”

OP GREAT BRITAIN.

Mr. Mot read a Paper, as follows, in
REPLY TO SOME REMARKS in the “ QUARTERLY
REVIEW” FOR 1875.

My attention was lately directed, through the vigilance of
our worthy Secretary to an Article in the “Quarterly Review ”
for 1875, on the subject of aeronautics ; and as the Article is
written, in some respects, with considerable ability, and yet
contains, in other respects, some of the most popular fallacies
in regard to mechanical flight, it occurred to me that a short
Paper on the subject might be of use in correcting such errors
and directing the thoughts of those who are working at the
problem into the right channel.

The writer of the Article in question expresses himself as
follows : —

“ There are many students of aerial locomotion who
profess a contempt for the balloon as a mere plaything, and
consider that the only proper solution of the problem is by a
flying machine which shall sustain itself in the air, like a bird,
by mechanical means. They disdain floating power, which
they say birds do not possess, and which is, therefore, un¬
necessary. It would be jus* as reasonable to propose, on
analogous grounds, to abolish boats and substitute swimming
machines. The ‘plus lourd que I’air ’ doctrine is a delusion
founded on the mechanical blunder of confounding gravity and
momentum, which are two distinct things. It is a more
reasonable objection that a balloon, from its large size,, must
offer a great resistance to the air at high speeds, but this
resistance has been enormously aver-rated, and is a cheap price
at which to acquire the first condition of aerial locomotion —
that of overcoming the action of gravity. At all events a
dirigible balloon is a thing actually in existence : a flying
machine is, at present, only an idea.” ?

aeronautical society

When I had read these remarks in such a work as the
“ Quarterly ” I drew a long breath and rubbed my eyes with
surprise and astonishment, as I considered that every writer of
ability had educated himself beyond this ; but, as I find that
such opinions are only too common, I will trespass upon your
time for a little while in order to put the matter in a clearer
and more correct light.

Although I am one of the workers at the problem of
mechanical flight I have a large amount of admiration for
balloons and the many able aeronauts who navigate them ; but
when I am advised to attempt to put balloons to a task
that they are incapable of performing, I of course treat
such advice with contempt (not the balloons, as the writer
asserts). If I am content to go a short distance through the
air, and in whatever direction the wind may happen to blow,
a balloon will serve my purpose very well, and, under good
management, it is doubtless a very pleasant and enjoyable mode
of travelling ; but if a definite course is desired, unaffected to
any serious extent by wind, then the balloon certainly becomes
a mere plaything, and recourse must be had to a mode of flight
which balances the effect of gravitation in another way, and at
the same time is capable of attaining a high rate of speed.

The writer in the “ Quarterly ” seems much taken with
the result of M. de Lome’s balloon, and says, in a foot-note,
that “the resistance to M. de Lome's balloon, of 122,000
cubic feet at 5 miles an hour, was only 21-glbs. ; at 20 miles
an hour it would be old lbs.’’ Very good indeed; but first of
all the writer must not assume that, because this air ship could
be driven at the extremely low rate of 5 miles an hour in still
air, that therefore she could be driven at 20 miles an hour and
keep her shape ; indeed it is very doubtful. But, assuming that
this could be done, let us see what power would be required.

If a steam ship requires a pull of 3441bs., the engine must

OF GEEAT BRITAIN.

give out an indicated power which would, by calculation, be as
100 is to 45, and it would not be safe to reckon on less than
43 indicated horse-power for M. de Lome’s balloon at 20 miles
an hour. The gas for this balloon cost £360., its capacity
being 122,000 cubic feet and the gas pure hydrogen. Its

floating power was as follows : — Tons.

Balloon, accessories, and instruments . 1*75

Crew of 14 men with baggage, &c . 1*13

Packages or cargo . 0‘27

Available ballast . 0*59

Total . 3‘74

These"! 4 men only drove it at 5 miles an hour, and I
have shown that 40 horse-power would be required to drive it
at 20 miles an hour. We therefore require, in order to carry
the Reviewer’s ideas into effect, a very costly balloon, very
costly gas, and a costly steam engine,- in order to go at the
miserable speed of 23 miles an hour ; and if a contrary wind
happened to blow at that speed all this costly apparatus would
be required merely to go nowhere, but just to hold your own
like a steamer on a lee shore in a gale.

I must also repeat the fact that balloons will not keep
their shape when opposed by a current of wind, and are very
much given to “ tearing ” operations.

I think I have quite justified myself in treating balloons
as mere “ playthings, and disdaining floating power which birds
do not possess.” I have also shown that the resistance to
balloons at high speeds has not been “enormously over-rated,”
for 20 miles an hour is an absurdly low speed, and at that
speed the game is not worth the candle, and a higher speed is
impossible with balloons ; in fact I do not believe that any
balloon could be driven at even 20 miles an hour.

aeronautical society

Even if I allow that a 40 horse-power engine could be
safely carried by M. de Lome’s balloon, and that a journey of
1000 miles can be performed at 20 miles an hour, and suppose
also that it can be performed in a dead calm, she would require
fuel for 50 hours steaming, which, as it would be impossible
to carry, she would want a number of coaling stations. I need
scarcely proceed any further : the whole idea is absurd and
impossible.

Secondly — The writer of the Article says : “It would be
just as reasonable to propose, on analogous grounds, to abolish
boats and substitute swimming machines. The ‘ plus lourd
que l' air ’ is a delusion founded on the mechanical blunder of
confounding gravity and momentum, which are two distinct
things.”

If we could breathe water instead of air the very best
mode of navigation by water would be after the style of the
torpedo boat,' under water — below the surface — and not upon
the water ; but as it so happens that water navigation is
effected in two elements, air and water, we must go upon the
water instead of under it. There is no analogy whatever and
no parallelism in the argument of the writer of the Article in
question. We cannot go upon the air ; we must go in it. We
can only go upon the water ; we cannot remain in it.

Again ; we find an abundance of practical illustrations of
living things in water, sustaining themselves both by displace¬
ment and by swimming, as cod, mackerel, <fcc., by displacement,
and soles, plaice, &c. by swimming ; but in the air we do not
find one living illustration of the author’s flotation theory, and
the reason is obvious. Water is 800 times heavier than air,
and therefore the bulk has to be increased 800 times ; and as
there is a wonderful power in the air to sustain rapidly-moving
planes, we prefer speed and thereby promote economy.

This brings me to the third head of my subject, namely,

OF GREAT BRITAIN.

that I consider (taking the words of the writer) “ that the only
proper solution of the problem is by a flying machine which
shall sustain itself in the air., like a bird, by mechanical
means.”

It is now eleven years since I published an Article in the
“Mechanics’ Magazine,” showing that high speed could be
obtained with sustaining planes without requiring greater power
than low speed, and not only so, but that the higher speed was
the most economical in every way. And in that Article I also
mentioned that, without a considerable expenditure in money,
the problem would never be solved. I consider that I have
some right to speak thus, having spent a large amount of money
and time in arriving at the highly-favourable results which I
obtained twelve months ago, when a 3-horse engine lifted
1201bs. dead weight, in the presence of some of the most
distinguished members of this Society.

Now, I will take the propelled aeroplane without gas, and,
taking the total weight at half-a-ton, 11201bs., I will allow an
aeroplane surface of 90 square feet, placed at an angle of one
degree from the horizontal. The resistance would be 0-375 of
a pound to the square foot, which, multiplied by 90, is equal to
33‘751bs., the speed would be 200 miles an hour, and the
vertical thrust 12'5lbs. per square foot; then

17,600 X 33 75
33,000

= 18 horse-power.

The engine power would require the same margin as before,
say 30 horse-power to effect the thrust of 18 horse-power
The weight of engine need not exceed 6001b., and fuel, aero¬
planes, frame, &c., with two persons, would all come within
11201bs., and be capable of going 200 miles an hour. Now,
suppose the journey to be 1000 miles, as before, the cost of the
fuel would not exceed £2. No £360. worth of gas has to be
supplied to the aerial steamer ; no damaged silk to be repaired ;

AERONAUTICAL SOCIETY

no ballast required ; a High speed attained so as to render the
game worth the candle ; a distance of 1000 miles accomplished
with an expenditure of about £2. in fuel ; the course chosen
with certainty, speed, and precision repairs and renewals of a
very economical description ; and safety far exceeding that of
any railway train.

In conclusion, I beg to say that I am not guilty of the
mechanical blunder of confounding gravity and momentum.
I know that they are two distinct things, and I have not over¬
rated the resistance due to gas bags at high speeds ; such
resistance increases about as the square of the speed, and is
capable of flattening the gas bag so as to reduce its contents
and compel it to take the most disagreeable course to aeronauts,
that of vertical descent, for as soon as a balloon is put out of
shape it loses in capacity and consequent ascensive power.

Mr. Moy illustrated his paper with a wooden screw, worked
by clockwork, the surface of the two planes being 1 1 sq. inches,
which, when set in motion, lifted a small weight, and was made
to travel either to the right or left in a circle by inclining the
orbit. He then, with another apparatus, exhibited planes
moved rapidly in a circle, which, although quite free to fall,
were sustained by the motion and upward pressure of the air,
and were quite incapable of falling while in motion.

Mr. Moy was also glad to be able to say that, by the
kindness and courtesy of his old friend Mr. Coxwell, who was
present and who had favoured him with the loan of two small
balloons to illustrate his subject, he could show them the
absurdity of attempting to drive balloons from the car, and, by
waving one of these to fro, it was seen that this often-proposed
idea is utterly useless ; but he shewed, at the same time, that
vertical assistance to balloons by means of screws was quite
feasible and practicable, preventing much expenditure of ballast
and gas.

OP GBEAf BRITAIN.

In conclusion, Mr. Moy informed the audience that his
patent steam engine was a commercial success, and although
he invented it for aeronautical purposes he was applying it to
other uses, and he was now having one made for a launch,
which would have a heating surface of exactly 100 square feet,
and from this he would be able to obtain valuable data, and he
then intended to make a 30-horse engine which would take up
two aeronauts vertically, and when the vertical ascent has been
obtained the horizontal movement would be an easy matter.

Mr. Brown said he would not go so far as Mr. Moy against
the balloon. Mr. Moy’s argument was against the globular
form of the balloon, but there was an observation made by
Mr. Moy which completely destroyed a great part of his
argument. Mr. Moy said it was very strange that a weight
completely immersed can be propelled better than when
partially immersed.

Mr. Moy : A torpedo goes uiider water with greater ease
than it would on the water.

Mr. Brown said that the deeper it was immersed in the
water the quicker the water closed behind it, so that fishes
swam better the deeper they were down. That was an argu¬
ment which told in favour of balloons and against ships. If a
ship was made round she would be quite as unmanageable as a
balloon. The proper form for a balloon was an acute angle in
front, disregarding altogether the angle behind, because the
velocity with which the air closed a vacuum was about thirty
times greater than water. Therefore they had the advantage
in the balloon of making their cleaving angle the whole length
of the balloon. In a ship they could not do that. The body
of a bird formed an acute angle. His beak, head, and neck
cleaved the air in a most admirable way. Therefore in the
balloon they should have a most acute angle so that the air
might not press but might glide off. If their angle was a

aMbonautioal society

certain length, and they made it twice as long, the resistance
would be diminished one-half, although the surface was
increased. When the angle was made very long the resistance
would be reduced almost to zero. He had great hopes that
this theory would be brought into practice.

Mr. Bbearey read a communication from Mr. Artingstall,
of Manchester, as follows : —

“ In the last Letter I wrote to you, that was inserted in the
9th Annual Report of the Aeronautical Society, I denied the
almost-universal opinion, even of eminent mathematicians, viz.,
that the resistance of air is as the square of its velocity, and
stated that the theory of the impact of military projectiles was
much nearer the truth. A single bullet or solid particle is as
the square of its velocity, but a stream of bullets or solid
particles, like a stream of air, would be as the cube of the
velocity, assuming that the whole of the momentum is expended
on the target or surface.

“ All matter, whether solid, fltud, or gaseous, theoretically,
is subject to this law ; but if a stream air is directed against
a surface a great part of its momentum is dispersed sideways,
in what we call ‘slip,’ rather a vague word, but perhaps it
depends upon the fundamental law, viz., that all free motion
takes the path of the least resistance ; however, one thing is
certain, that slip is, beyond comparison, the most difficult
subject to deal with in aeronautics, yet this property is highly
favourable to progressive flight, for all bodies shaped like a
bird, and moving in one continuous direction through the
atmosphere, experience comparatively very little resistance, but
surfaces vibrating 'in a peculiar manner lay hold of the air
powerfully, hence we see the wonders of flight achieved by
this combination of the minimum of resistance with the
maximum of propelling power, for there is no real slip in true

OF GREAT BRITAIN.

flight. How is this wonderful vibration accomplished? I
believe that the double vibration of the wing (that is the
up-and-down stroke) is excited chiefly by the single pull of the
great pectoral muscle, and riot only so, but the buoyant or
propelling power is all transferred to the under side of the wing
and maintained there without cessation, also the bird or bat
progresses steadily, notwithstanding the wings may not be
propelling in a line with the centre of gravity.

“ The following may bear on this subject. In the Letter
just referred to I called your attention to a curious effect
produced by suddenly cutting the air with the thin edge of an
elastic wing, thereby producing a singular pulsation. Since
then I have experimented farther. Instead of merely striking
the air a single stroke I fixed a light and strong artificial wing
at the end of a round and slender rod of highly-elastic steel, thus,

and gave it a circular motion impelling the thin edge A against
the atmosphere. A Series of beautiful and rhythmatic pulsations
took place with powerful hold upon the air ; in fact a buoyant
rotary and vibrating wing (not a screw) but in theory of action
resembling a bird’s or bat’s wing. It must be understood that
the circular motion was a substitute for a blast of air.

“ But to modify this experiment and make it more nearly
resemble a natural wing, I took the wing and its steel rod from
the rotating machine and exposed it to a very strong wind on
an elevated situation. It vibrated similar to what it did in its
‘ orbit ’ motion, but in the wind its curves of vibration could
be much better observed, yet it was too quick to be properly
traced by the eye. A larger and consequently a slower moving
wing must be constructed, but so far the results are very
encouraging, and I conceive may be practically adopted.

AERONAUTICAL SOCIETY

“ When my experiments are more advanced I may make
them the subject of another Paper.

“ There is every reason to believe that long and narrow-
winged birds, such as the albatross, swift, common swallow, &c.,
when they have acquired their initial velocity, go through their
wonderful evolutions, in a perpendicular mass of air, with com¬
paratively less expenditure of power than a good skater does
on a horizontal plane of the best ice and with far grater speed ;
in fact it appears as if the long- winged birds have very little
more to do than first acquire momentum and then steer it.
At all events very little power is required to overcome the
resistance of the atmosphere to progression, and, theoretically,
the momentum lost in ascent is nearly regained in the succeeding
descent, and rapid ascent is generally accomplished by swift
birds quickly directing their momentum upwards, and not by
great labour as the sparrow reaches the house-top.

“ I may, in conclusion, remark that all artificial vibratory
wings, like those of the bat (hitherto constructed), require
enormous power compared with the small weight raised and- the
short duration of flight, my experiments mentioned in the
Annual Reports of the Aeronautical Society for 1866 and 1868
being no exception ; therefore we must endeavour to improve
the vibrating wing by ascertaining its true principle of action.”

Mr. F. Cayley-Worsley said it struck him that the
very nicely-adjusted science they were engaged in, required
very careful experiments, and he did not hear that those
experiments had been made at all on an efficient scale. He
had made many experiments as long as the power lasted for
the balancing, steering, and adjusting of aerial apparatus ; but
to set a steam engine going without giving adjusting power,
must result, as it seemed to him, in utter failure. He had seen
many of the experiments of Sir George Cayley, who was

OF GEEAT BEIT AIN.

called the “flying baronet,” and he was convinced from
these that they must have a convenient experimental
power. In his opinion there was a means of getting experi¬
mental power without going to the expense of steam engines
or any large machinery, and the question was whether the
Aeronautical Society was inclined to go into anything of that
kind ? He believed compressed air could be used as a temporary
motive power. If they could get power to go 100 yards they
could easily get power to go beyond that distance. He did not
see in what other way than by experiment they were to succeed
with a machine which required the marvellous adaptability of a
bird. He should like to see a compressed air engine made which
would give an eight or ten minutes’ run ; then the engineer
would be able to take data. Without data it was an extremely
difficult question which they had to contend with. The engine
made and exhibited at the Crystal Palace appeared to his mind
to have sufficient power to move off the ground ; but, to a
moral certainty, it would have turned head over heels. Well,
did it not follow that, unless they had carefully adjusted the
centre of gravity they would certainly come to smash ?
(Hear, hear.)

Mr. Moy said he could assure him (Mr. Cayley-Worsley)
that he had paid great attention to the subject of balancing.
It would be very foolish not to do so. In the experiments at
the Crystal Palace the friction on the ground was so great that
they could not get more than twelve miles an hour in a
horizontal direction, and, therefore, it could not rise ; but when
they tried the vertical movement they got a lift of 1201bs.
with 3-horse power. He did not see why a 30-horse engine
should not be made right off. He had seen many miserable
attempts made with springs, but just as the machine was
rising, the power was gone and the machine stopped. He
maintained that a 30-horse engine properly applied to aero-

AERONAUTICAL 80CIETY

planes would raise not only itself but two aeronauts. When
such an apparatus could go straight up and come down as
gradually as it went up, then they might talk about horizontal
movement. He quite admitted that care was required in
balancing, and balancing should certainly receive the greatest
attention after the necessary power, for the upward movement
had been obtained.

Mr. Brown : As regards the difficulty of balancing and
control I think I have completely cured that.

Mr. Mot : Why did you not put an engine to your model ?

Mr. Brown replied that it had only been tried on a small
scale. It always came down in the same way that it went up. Of
course he considered the balancing the most important part to
deal with, and they could not proceed further until they had
mastered that which he believed he had done. Still he should
like to see it tried on a large scale. He should like to have to
contend with unequal currents, which they could not find in
a room.

Mr. SEnEcal remarked that whatever experiments were
made there ceziainly must be a man to guide, and the. steering
apparatus must be independent of the power that moved the
wheels.

Mr. S£n£cal gave some notes on aeroplanes of different
forms, some loaded with weights, which he illustrated with
paper models.

He said that while planes of even width and thickness
revolve upon their own axes, and their path of translation
is rectilinear, the motions of triangular planes are much more
complicated. These planes are obtained by dividing the cir¬
cumference into blades of different widths. These blades,
besides revolving upon their axis, rotate also round a vertical
conic axis, whose base is upward, the vertex of the plane
describing a spiral round the conical axis.

OF GBEAT BEIT AIN.

He found that the rate of revolution and rotation increases in
direct proportion as the base and the length of the blade decreases,
and the length travelled over in a unit of time decreases also in
the same proportion. The shifting of the centre of gravity- of
these blades is most interesting. It was found that the centre
of gravity of narrow planes was near the vertex and on the edge
of the plane, but recedes towards the base and axis as it widens 5
it also travels from the axis towards the edge and vertex as the
rate of revolution increases, and possibly that, at high velocities
of rotation, the centre of gravity will be beyond the edge.
The size of blade that revolves and rotates most steadily
represents the 18th to the 24th part of the circumference. He
also proved that by cutting a small plane out of the base it
had the same effect as applying a weight at that point before
cutting it. The plane will then revolve and rotate round
with its base turned towards the vertical axis.

Mr. SisnJsoaii then enunciated the following law : that
planes, of whatever form, but of even thickness and rigid
margin, in order to translate steadily, must carry their
maximum load on a line representing the first 3rd part from
the anterial margins of the plane ; but one can, with impunity,
apply graduated weights from that line right on to the edge,
and, in some instances, a good distance beyond the edge, and
high rate of speed is the result. The rate of translation
increases directly with the load placed on the different points
of the graduations from that line of the centre of gravity.

He also liberated several narrow strips of paper showing,
while revolving, nodal and ventral sections similar to musical
strings in vibration, the number of aliquot parts increasing with
the length of the ribbons and disappearing as the width increases.

A Gentleman present, referring to Mr. Senecal’s experi¬
ments, called his attention to the fact that small objects in
water sank very slowly and large objects rapidly.

AERONAUTICAL SOCIETY

The Chaibman said there was one observation he would
like to make with respect to the little machine which had, that
evening, been sent through the air, but, as far as he had seen,
its motions were somewhat erratic. Now he was quite
confident that if the two wings instead of being on one plane,
were more inclined to each other, it would not veer about
as at present shown, but would fly steadily. If it found
itself turning sideways one wing would counter-balance the
other, and the machine would have a tendency to steady itself.
The wings should, therefore, be put at an obtuse angle to each
other. As all the communications which were put down for
that evening had been made, he would invite those present to
return their best thanks to the Authors for the several com¬
munications which had been made, and he trusted some of
them would lead to practical results and so be conducive to the
great end they all had in view.

Mr. Moy proposed a vote of thanks to the Chairman for
his kindness in presiding over that Meeting.

The Mention was adopted with acclamation.

The Chairman said he was glad to have an opportunity,
in the smallest degree, of promoting the object they all had
in view and of furthering the interests of that Society.

The Meeting then separated.

OF GREAT BRITAIN.

THE POWER DEVELOPED BY BIRDS,

A. PENAUD;

Read before the Society Philomathique de Paris

in 1876.

In 1866 Mr. Wenham* pointed out that birds whilst in
rapid flight encountered at each instant a fresh undisturbed
body of air, and dispensed less power in full flight than in
hovering. M. de Lauvire showed also, about the same time,
the advantage of the oblique action of surfaces upon the air,
in taking for basis the experiments of Thibault.

I have been able to establish the very simple law of the
resistance to flat surfaces moving at very oblique angles in a
fluid, and I developed their result in 1872.

By introducing in my calculations the results of several
observations that I have made upon the different species of
birds, I detennined very nearly the work dispensed by them in
full flight, this work was equivalent according to the species
and the size of wings, to the elevation of the weight of the
animal from 20in. to 5ft. per second, and generally superior to
40in. for the large species.

My calculations, founded upon a number of concordant
experiments and upon a series of observed facts and theoretical

* Mr. F. H. Wenham is one of the Council of the Aeronautical
Society of Great Britain. — Ed.

AERONAUTICAL SOCIETY

considerations, since that time have been applied to other
purposes. I will mention the remarkable experiments made
by Mr. Froude for the English Admiralty upon planes gliding
on the surface of the water, and some made by M. Marey with
planes rotating on a stand, and also in direct translation along
an iron wire.

After having determined the work dispensed by birds in
normal flight with these calculations, and also by other and
independent means, I thought it would be of great interest to
know the maximum power that birds were able to develop for
a given time.

They require in certain circumstances a superabundance
of strength, and flying machines that may be constructed in the
future will also require, in though a less manner, a store of
power upon which they can fall back in emergency ; great
power will be wanted to start from the ground.

One of the cases in which birds develop considerable
power is, when they ascend almost vertically from the ground
to a high perch, and it is then easy to watch them with
precision, and make some nearly exact estimates. The bird
in these ascents appears to develop almost the greatest
amount of power it is capable of, for I have often seen pigeons
still young only able to reach half-way to their cot, owing to
excessive fatigue.

They have at last succeeded by ascending in a spiral of
considerable extent, thus augmenting the duration of their
flight, but, at the same time, owing to the forward movement
diminishing the amount of work developed per second.

This fact is often observed when the young pigeons have
taken a bath and their body and especially the wings are
charged with humidity.

In the ascent the total work developed by the bird is
divided into two parts, the one fixed, that is the work of

OF GREAT BRITAIN.

elevation, the other variable and increasing with the time, that
is the work dispensed in finding a support in the air.

It is thus to the interest of the bird to rise as quickly
as possible, which it generally does even when under no sense
of fear. Their velocity of direct ascent is always several yards
per second.

I have been able to measure with considerable accuracy
the direct velocity of ascent of the’ stockdove when rising to a
perch 35ft. 4in. from the ground. The mean velocity of ascent
taken from 8 flights was 9ft. lin. ; the mean of the two
slowest flights was 7ft. 7in. ; and of the two most rapid
lift. 7in. The ringdove gave a mean of 9ft. llin.

I have made 15 observations of sparrows whilst mounting
from the ground to a wall 28ft. lin. high, and found a general
mean velocity of lift. 3in. ; mean of the two slowest 9ft. llin.,
of the two fastest 14ft. lO^in.

This is the mean velocity in an upward flight of consider
able length ; but we must remember the bird starts without
velocity, and settles in the same condition, so that in the
middle of the flight the velocity is vastly greater than the
above figures show.

If we assimilate the movement of the sparrow to that of
a pendulum, which is plausible enough, we find the velocity in
the middle of the ascent would be 16ft. 6-^in.

For peacocks, which are heavy birds, who came every
evening to pass the night upon the same tree, I found a
velocity of 8ft. 3in. They rose in 2*6 seconds to a branch
21ft. 6in. from the ground, and in starting helped themselves
by a vigorous stroke with their feet.

Amongst the birds that mount most rapidly are partridge,
wild turtledove, and snipe, which are of moderate size, but
provided with powerful pectoral muscles and small wings.

The sea-pie rises more rapidly still, and in some observa-

A A

AERONAUTICAL SOCIETY

tions, not very exact owing to absence of convenient marks by
which to measure the height, I found an ascent of about 20ft.
per second.

Thus, and apart from all theory, it is certain that birds
are capable of developing momentarily a force corresponding at
least —

For the Peacock, to one horse-power for every 661bs.

Ditto Pigeon (Stockdove and Ringdove) 571bs.

Ditto Sparrow ... ... ... 48-^lbs.

Ditto Sea-pie ... ... ... about 261bs.

As before mentioned the work of elevation is not the only
one the bird has to do ; it has still to find a support in a fluid
extremely mobile. When a bird rises vertically without any
horizontal movement and maintains itself upon the same
column of air it throws the axis of its body into an almost
vertical position, and the direction of the motion of the wings
is almost horizontal. The amplitude of the stroke of the
wing is very considerable and embraces the entire circumference.
In the pigeon the extremities of the wings are often heard to
strike each other.

The change in the angle of the plane of the wing at each
oscillation is very great and exceeds 90°.

The wing, conveniently twisted upon itself, acts upon the
air with great power during the down stroke, after the manner
of an inclined plane ; in the return stroke the wing still acts
upon the air, but to a less extent and with its superior surface.

It then forms inclined planes in contrary directions, and
receives back the horizontal impulse given to the air by the
wing in the preceding oscillation.

The wings act thus in a similar manner to the tails of
certain fish, describing in the air put in motion a sinuous path
in the form of very close spirals. It flies after the manner of
a helicoptere, its body held vertically representing the nave,
and its wings the blades of the screw.

OF GREAT BRITAIN,

By means of these horizontal oscillations of the wing of
great amplitude, the bird acts upon a column of air of the
greatest possible section, and having for base the circle des¬
cribed around the body by the wings. Vertical oscillations,
excellent in full flight because the translation constantly brings
new stratum of air under the wings, would be very disadvan¬
tageous in an almost vertical ascent, for it would put into
motion a column of air far more restricted. I have found that
the bird in vertical flight and in hovering creates an almost
uniform current of air by means of the rapid succession of the
oscillation and intensity of the changes in the plane of the wing.

The section of the current is evidently the horizontal
projection of the area passed over by the wings. I have con¬
firmed this by making a pigeon mount in smoke and in a net,
with large meshes, covered with light bodies such as down.

When the Sphinx is suspended over a flower for the
purpose of getting the juice, the foliage immediately below is
visibly agitated in a continuous and regular manner by the
current of air thrown from their little wings.

By blowing some smoke through a small tube into the
current its dimensions and regularity are rendered still more
visible.

By waving transversely near a candle the wings of a bird,
freshly detached, or artificial wings, a nearly uniform current
is easily obtained, of which the extent can be measured.

When a helicoptere, or an artifical bird of my construction,
is presented to the candle, a uniform, continuous, cylindrical
current is produced without dispersion or centrifugal move¬
ment.

I have brought one of my helicopteres in order to make
this experiment before the Society. It is seen contrary to the
general opinion, that the air far from being dispensed .at the
circumference of the screw, tends to converge toward its axis,
which is shown by the slight attraction of the flame.

AERONAUTICAL SOCIETY

Behind the screw, or for a considerable distance, the
candle experiences only a feeble agitation as long as it is out¬
side the cylinder, having for base the circle of the screw ; but
when it enters the cylinder it is violently blown. If the light
is placed in front of the screw it is seen that the column is not
continued, and that, immediately in front of the screw, a
widely extending cone of suction is formed, which takes the
air from all sides.

The same effects are produced by screws whose blades
are inclined forward, and also when the screw is moved
backwards or forwards along the column of air in motion.
These facts show that the work dispersed by the bird, in order
to find a support in the air which gives way beneath him with
a velocity W, differs but little from the work necessary for
maintaining an uniform speed W, in a tube having for section
the horizontal projection of the area described by the wings
*f the bird.

In taking this last work as that of the bird, we shall be
certain it is a minimum ; for the uniformity of the movement
of the air put in motion by the bird is not absolute, as there
certainly exist eddies resulting from the impluse of the air
directly struck by the wings acting on that more remote ;
but it is known that when a mass of fluid m with a velocity V,
draws with it by lateral communication, another M at a
velocity U we have m V = (M + m) U, and this formula,
demonstrated by the experiments of M. Piarron de Mondiesir
upon ventilation, by means of compressed air, involves the loss
of momentum ; but the loss of energy is small when M is
mediocre relatively to m, and we have seen by its proved
uniformity near the wing that such is the case with the
currrent of air put in motion by the bird.

If P is the weight of the bird, l the length of its wing,
£ the arc described by the wing in the mean, plane of its

OF GBEAT BRITAIN.

oscillation, X the angle of this plane with the horizon, the
section of the vertical descending current put in motion by the
two wings will be l 2 arc £ cos. yj.

In order to get the volume acted upon per second the
preceding expression must be multiplied by the length of the
column of air put in motion during that time.

In stationary flight this length will be exactly the velocity
W of the current, but in the case of flight ascending with a
speed h, this ascent causes the constant creation of a current
in a fresh body of air, owing to the singular form of the cone
of aspiration, and the support is thus greatly increased.

It is in this manner that the screw of a steam-ship when
acted upon by a constant force, turns but very little faster when
the ship is going at full speed than when fastened to a fixed
point ; in / the first case however, the slip Is less than

100

whilst it is equal to the whole in the second case.

From this I think, in the present case, we may take for
the length of column of air acted upon per second W + h
(perhaps it would be better to take W + f h, f being a certain
function of l, W, and h ; but in the absence of exact data we
will retain W + h ).

This being settled, if it is the weight of the entire volume
of. air, and g the acceleration of the weight ; the mass of air
put in motion during one second by the wings will be

t) = * l2 arc £ cos. rj (W + h),

y . .

and the work expended per second in maintaining the current

T = = f l* arc C cos. ,(W + A)W^ = PW;

from whence we get _

w=U-4 + v * + „ 8— — )

^ \ v l2 arc ? cos. ij./

The positive root alone must be used here.

AERONAUTICAL SOCIETY

It is seen that in stationary flight where h — o the work
varies proportionably to the power of the weight of the
bird, and in an inverse ratio to the width across the wings
(that i3 to say, the square root of the surface in the case of
similar surfaces).

We will apply this formula to the ringdove, of which I
have measured a great number, and found the several means
to be P = 480gr l = 0m, 82 S = 160° y = 20°.

We have besides y = 1\ 24 (mean condition), and h = 3m.

It results that W = 4m, 1 (a different method of calcu¬
lation has given but slightly different results).
h .

— - = 0'42 gives the thrust of the wings as elevators.

The elevation W 4- h, corresponding to the total work of
support and ascension, is 23ft. 3in.

But we have not yet taken into account all the conditions
of flight. I am convinced that the inertia of the wing, in spite
of its marvellous lightness, absorbs a considerable amount of
work. For want of time I will not enter into the details of
these researches, but will content myself by saying that I have
arrived at exact results by means of weighing different portions
of the wings of birds and insects, by making an integral quantity
of the moment of partial inertia with respect to the scapulo¬
humeral articulation, and by introducing the factors thus
obtained in formula, taking account of the number and
geometrical conditions of the oscillations of the wings. Applied
to the ringdove these calculations give more than 6ft. 7in. to
be added to the 23ft. 3in. already found.

This number which takes account of the useful absorption
of the momentum by the resistance of the air at the end of
the stroke, corresponds after a manner of its own to a maximum
k forming part of it and W also, in a great measure, owing to
the want of translation. In forward flight, the oscillations of

OF GREAT BRITAIN.

the wings being less rapid and numerous, the work of inertia
is far less : moreover the absorption of the momentum by the
resistance of the air is complete.

In the presence of this enormous figure of more than
6ft. 7in. I have been led to think that the elasticity of the
wings and muscles play an important part at the end of the
stroke, and that the wing acts as a spring similar to a timing-
fork in vibration. The admirable elasticity of the feathers and
ligaments of the wings seem to agree with this theory. I have
found, by experiment, that a feather is twice as elastic as steel,
weight for weight. The muscles, when contracted, probably
possess the power of storing up and restoring, to a certain
extent, power like a spring. The work absorbed by the inertia
is not wholly restored, and it is certain that it causes the total
work of the ringdove to correspond definitely to a height of at
least 26ft. 3in. per second, or 201bs. per horse power.

I have arrived at results still more astonishing, in some
calculations founded upon observations made upon the flight, at
full speed, of the martin and sphinx.

Such is the maximum dynamic power that birds are
capable of developing. It is considerable and very superior to
that of mammalia and man in particular. It has not, however,
happily any connection with the fantastic calculations of
Naivier. He dared to declare that the swallow flying at 50ft.
per second developed power corresponding to an elevation of its
weight to 948ft. per second.

Let us compare the power of a bird with that of man and
the steam engine.

A man is able, during several hours, to climb a ladder at
the rate of 6in. per second. The ringdove, which can fly also
for many hours together, dispenses in full flight power equal to its
own weight lifted 3ft. 7^in. per second. The proportion is thud
22 to 3.

AEBONAUTICAL SOCIETY

By making a spurt I have found that a man can ascend
to the 4th floor with a mean speed of 3ft. per second ; but this
experiment was made under disadvantageous circumstances.
An athlete could do far more. If we compare this figure with
the corresponding one of 23ft. 3in. total work expended by
the ringdove in a vertical ascent, the proportion here is 7*9 to 1,
and nearly the same as for the normal work.

The lightest motor that man has yet constructed is the
non-condensing high-pressure expansive steam engine, such as
express locomotives, steam fire engines, and the engines of fast
steam launches. None of these weigh less than 661bs. per hoiee
power with only a very small provision of water and fuel ; com¬
pound engines with surface condensers as at present used in war
ships and mail boats weigh at least 2751bs. per horse
power. In a flying machine the weight of the motor
should never be more than a fraction of the total weight.
According to my calculations it should not exceed Jrd, in order
to leave sufficient weight for the supporting surfaces. Thus
the actual motors we have, are far from equalling the power
that the bird develops under certain circumstances, and even
unable to develop the far less power that large birds expend in
full flight for hours together by supporting themselves upon
vast masses of new and undisturbed air.

Allow me, however, to express my conviction that, in the
future more or less distant, science will create a light motor
that will enable us to solve the problem of aviation.

Or GREAT BRITAIN.

LAWS RELATING TO PLANES GLIDING IN THE AIR.

ALPHONSE PfiNAUD,

Translated from “ l’Aeronaute ” by T. J. Bennett.

Newton, who was the first to study the resistance that
fluids offer to a body moving in them, stated implicitly that
the molecules of the fluid remained immovable up to the
moment that the body touched them, and returned to a state
of rest immediately afterwards.

He found that the resistance experienced by a flat surface
was proportionate, 1 ^ to its extent, 2° to the density of -the
fluid, 3° to the square of the velocity, 4° to the square of the
sine of the angle of incidence, and 5° that it is normal to the
surface. It was, however, soon discovered that this theory,
altogether empirical, was often at discord with what .experience
taught, and a great number of experimental researches have
been made at different periods in order to throw further
light on the subject.

The result of these researches has been to prove that the
last, and second laws are in a great measure true, also the third,
except for excessive velocities, as in the flight of a cannon ball ;
but the first law does not hold good except for surfaces of/
similar shape and position. The same surface experiences,
other things being equal, a great difference of resistance,
according to the shape of the body of which it makes part, and
its position in that body.

AEBQNAUTICAL SOCIETY

The law of obliquity is altogether false. The results of
experience differ greatly, sometimes less, but generally in excess
of those given by the law.

As we have not been able to discover the laws of these
complicated facts, we have thrown the anomalies presented
between practice and theory upon the imperfections of the
experiments made, and still continue to teach the laws, pure and
simple, of Newton.

It was in applying them to the resistance experienced by the
wings of birds that Navier (who besides was entirely ignorant
of the mechanism of the wing) made his exorbitant calcula¬
tions, and thus, in a great measure, was the cause of throwing
aviation into t'he discredit from which it is now only beginning
to emerge. These calculations were entirely contrary to facts,
since, for example, he gives more than 12 double beats of the
wings per second to the raven, who in reality only makes 3.
A great number of daily phenomena have equally opened our
eyes to the enormous resistance experienced by thin surfaces
moved obliquely, viz. — the sailing of a ship close to the wind,
the power given out by windmills, the thrust of a screw, the
power of a rudder, which all give (quite an exceptional thing)
better results, -in practice than in theory. Thus these laws of
Newton are not universally adopted, especially in naval
architecture, where views more in accordance with experimental
facts are adopted.

It is acknowledged by those who have studied the subject
of aviation that the bird develops vastly more power in hovering
than in ordinary flight, when its wings attack the air at a very
small angle, which is easily perceived by watching a bird
coming directly towards you when only a little more than the
edge of the wing is seen. This fact, the key of aerial naviga¬
tion, has been noticed by several persons, amongst whom are
the Duke of Argyll, M. de Lucy, and the Count d’ Esterno, the
author of the well-known book on flight.

OF GREAT BRITAIN.

Mr. Wenham, in his valuable Paper printed in the First
Report of the English Society, has developed this idea, that
flight is a phenomenon analogous to the collision of two bodies,
and that the greater the mass of air attacked in a certain time
the less will it be put in motion, and the work dispensed con¬
sequently less. He came to the conclusion that it would be
advantageous to use a long and narrow surface like the wing of
an albatross, moving rapidly at a very small angle, so as to act
upon the greatest amount of air possible. He was thus the first
to perceive the cause of the advantage of attacking the air
obliquely, and the part played by the great spread of wing in
the albatros and other long-winged birds, for if upon the
spread of wings principally depends the surface of the stratum
of air attacked, the mass of this air depends upon its thickness,
which evidently diminishes with the size of the surfaces
employed.

Lastly — M. de Louvrie, having carefully studied the
subject, published several Papers, amongst which was one that
appeared in V Aeronaute for 1868, where he reproduced the
results obtained by the most trustworthy experimentalists with
surfaces presented at a small angle to the air, and insisted, and
justly, that the results obtained by Thibault, which are
indisputable, are the most applicable to flight.

, The figures of Thibault show that for plane square surfaces
the resistances normal to the surface remain nearly constant
from 90° to 45°, and after that diminish progressively to 20°,
from which to 0° it becomes sensibly proportionate to the
simple sine of the angle of incidence. At 14° the pressure was
about half of that experienced in the normal position, the
speed being the same.

It was reserved for M. de Louvrie to bring to light these
results and to demonstrate them to be in concordance with the
flight of birds, and also show, by a rigorous analysis, the
advantage of attacking the air obliquely.

AERONAUTICAL SOCIETY

The above studies having opened up the subject, the
Paper I have presented to the Society is a sequel to them.

As the surfaces of all flying beings, in spite of their variety,
possess important points of similarity, we have used the laws
of Newton, making, however, the resistance proportionate to
the simple sine of the angle of incidence, which, as we have
seen, increases rather too rapidly, except just for small angles
with which we have principally to deal.

THEOREM I.

A bird that glides, falls the least possible distance when
it employs for progression a quarter of the power of the fall.

Let us consider a bird gliding with a uniform movement,
the plane of its wings AB being inclined at the small angle a,
below the horizon AH. It will descend along the line AM,
inferior to AB and forming with it the angle BAM = £.

Then let P be the weight of the bird ; V its velocity ;
S the lower surface of its wings ; c sine 1 ° the normal resist¬
ance that a surface similar to S, but 1 mq would experience
when moving at an angle of 1° and a speed of 1 metre
per second ; S' the projection of the bird upon a plane
perpendicular to the plane of its wings and the axis of its body ;
e'S' the resistance that the bird experiences in advancing along
this axis with a velocity of 1 metre ; T the work given out
during the fall in one second, being the sum of the work T\ and
T% of suspension and propulsion.

OF GREAT BRITAIN.

As the bird is sustained by its surface S, the vertical
component of the resistance of the air upon S balances the
weight P : we thus have cS V‘! sine £ cos. a = P ; but as a is
small, cos. a is sensibly equal to one, and we can thus write
simply cS V2 sine £ = P. (1)

The work of suspension during one second is
7\ — cS V3 sine2 £.

Substituting for V in this equation its value got from (1), we have

7\ = P\/I \/ sine £.
cS

This remarkable conclusion shows us, that in the uniform
movement of a plane gliding in the air, the work necessary for
its suspension diminishes at least proportionately to the square
root of the sine of the angle with which the air is attacked.
The work necessary thus tends towards zero when the velocity
is increased indefinitely.

But the work of progression, which is nothing if £ = 90°
increases as £, is less. The total work T = Tx q- T2 has thus
a minimum corresponding to a certain value of V, and conse¬
quently of a and £.

But taking into account the smallness of c'S' in comparison
with cS, in all birds and bats, it is seen at first sight that
£ will be small, as will also the value of a, which is necessary
for the maintenance of the impulse. (This will be verified
further on.)

We shall now have T% — c' S' V3,

And T= h + T% = cS V3 sine2 £ + c'S' V3. (2)

Let us find the minimum of this quantity. Fi'om (1) we

«et 3i"*S C = ? -gry.

Substituting it in (2) we have 7' = -f c'S' V3.

AfiBONATTTICAL SOCIETY

As an equivalent to 0, the derivative of the second mem¬
ber in comparison with V, we have the value of V corresponding
to the minimum of T.

8c'8'v’-iV> = a

From whence V4 =

(3)

3 cS c'S'

(The second derivative is besides positive : this value
corresponds well with a minimum.)

c'S’

We then have sine2 £ = 3

a, the resistance to the forward motion, being evidently
equal to the compounds of the weight parallel to the plane of
the wings, we get c'S' V2 = P sine a, from which we deduce
• „ 1 c'S'

sine 2 a. — - — — sine C = 8 sine a.

o cS

The work T becomes

cS CO

Lastly, the comparison of the work of suspension to the
work of propulsion is, as we have stated, found independent of

data ~ = 3.

Note — If in place of using the law of the simple sine of
the angle of incidence we employ the sine", we have
T\ sine £ 3 n

T2 sine a 2 — n

which shows that, according to the old law of sine2, the most
economical planing would be a vertical fall.

THEOREM II.

A bird moving at a uniform velocity travels, in gliding a
given distance, with the least fall possible, when the work of

OF GREAT BRITAIN.

suspension is sensibly equal to the work of translation. The
plane of the wings then divides into two equal parts the angle
formed with the horizon by the path of the bird, and this
angle is itself as small as possible.

We see from this that the path followed by the bird is
nearly horizontal, for to say that the fall is at a minimum in
travelling a given distance is equivalent to saying that, for a
given fall, the bird travels the greatest distance, and conse¬
quently in the nearest possible path to the horizon.

Retaining oui- notation, except that T 7\ T2 do not now
refer to a second of time, but to the total time necessary to
travel the given distance which we will call e. we have

e = Vt (1)

cS V2 sine P = P (2)

T = 7\ + 7*2 = cS V" sine2 P t + c'S' V3 t (3)

From (2) we get V2 = — — 7 - -

cfe sine P

Multiplied by ( 1 ) it becomes V3 t = — -

cS sine P

Substituting it in (3) we have T = eP sine P + .

cS sine P

It is this quantity that must be reduced to its minimum.
This will be when 7\ = rl\ since the product 7\ 7’., is constant

Ti = T2
„ c'S'

We find then sine2 P = = sine2 a

"Ho

We have also V4 =

c 8 c'S'

And the work per second - = 2P A , / \ / c ^

1 v cS 7 cS

from which we learn that the work is here f of that given bv
the former theorem, while the speed is equal to f..

If the direction of flight is against the wind it will give

AERONAUTICAL SOCIETY

the advantage of augmenting the speed. In the case of a
favourable wind it would, on the contrary, be similar to the
conditions of the preceding theorem.

Note — The law of sine” gives

T\ sine £

= n.

__ . ... and for

T-i sine a

the law of sine2 7\ = 27 2. We see, then, that even in this
hypothesis the translation requires still a third part of the
total work.

III.

In these calculations it is taken for granted that the
resistance to the forward motion is small compared to the

c S’

resistance of the descent, or. to be more exact. — is small.

c b

which is always the case in flying beings, excepting a few
insects.

It is the same in the case of a surface that is inclined
above the horizon instead of below it, and being moved in a
nearly horizontal line instead of falling under its own weight.
We are thus able to get valuable information, not only con¬
cerning the flight of birds, but upon the value of a greater part
of the proposed systems of aviation.

We shall now notice the most general of the numerous
consequences of these calculations.

1st — Every one knows that the ordinary flight and the
gliding of the same bird are always in concordance with regard
to speed, maintenance, &c. : that it can immediately pass from
one to the other with great facility, which fact proves their
near relationship. In fact the bird in ordinary flight moves at
an almost uniform velocity, and may be considered as a plane
gliding at small but variable inclinations, and it has even
(so much does the economy of ordinary flight permit) the
advantage of attacking the air almost at the same angle over
its whole surface. It is thus certain that the preceding

OF GREAT BRITAIN.

calculations are applicable to ordinary flight, at least as to the
form of connection established between the different elements
of the problem, the co-etticients alone being slightly changed.
All that follows applies to every kind of forward flight.

2nd — e'S', c S, and P differ but little in the same species
of flying beings, but vary in different species, and thus the
necessity of determining for each specie its own proper ’velocity.
This velocity will be greater as c*S and c'S' are less and
P greater, in other words that the bird will be heavier, possess
less sustaining surface, and be a better projectile.

Thus we explain the fact which has astonished many
naturalists, that a bird with wings relatively small generally
flys better than those with large wings.

We also understand the reason why birds reduce the area of
their wings and shut their tails when they wish to fly quickly,
for instance the ringdove. It is owing to" the power of varying
the area of their wings that birds possess such suppleness of
flight. Insects and bats not possessing this power have an
eccentricity in their movements similar to those made by a
sheet of paper abandoned to itself in the air.

3rd — The work expended per second in order to sustain a
given weight is proportionately less as c S is grearter relatively
to the weight.

This rule shows that a bird has more labour to sustain
itself the larger it is, for, the amount of surface per kilogramme
is as the inverse of the size. This has been thought by many
the rock upon which aviation would be wrecked. It is
necessary, however, to remember that the flight becomes more
rapid as the bird is larger, so much so that if the work per
kilogramme and per second increases with the size the work
per kilogramme and for a given distance remains independent
of the weight P of the bird, the largest bird therefore being
able to make at least as long a flight as the small ones.

AERONAUTICAL SOCIETY

From another point of view this difficulty of suspension in
machines capable of carrying men. which we must boldly face,
must not be so much deplored, for if we possess the same
facilities of suspension as the small birds we should also have
their restricted speed : but the special aim and necessity of
aerial navigation and, above all. aviation, is speed, and it is
easier to obtain it in a large machine than a small one.

4th — The work expended depends a great deal upon e'S'.
so that when the resistance of the machine to the forward
motion is reduced, not only is the speed augmented but the
work necessary for its suspension in the air is also reduced.
It is for this reason that birds are formed and feathered in a
fashion to make good projectiles, especially the good flyers, and
also why they draw their legs up under their tails and stretch
out their necks. If the heron does not do so it is because its
body would still remain so ill-shaped, and the reduction in the
resistance would not compensate for the fatigue. It does do
it, however, when pursued by a bird of prey.

If large wings indicate easy flight (for it is evident that
nature has not made them without a cause) small ones do not
necessarily show small power of flight, if, the pectoral muscles
are powerful, or even if the body is a good projectile ; for
instance king-fishers and ducks.

All birds with angular bodies, and which have to fly
considerable distances in order to find subsistence, are furnished
with ample wings ; the gralla for instance.

On the other hand the divers with spindle-shaped bodies
are able to effect their migrations with a minimum of wing
surface.

A great development of the parachute surface, especially
when the weight is small, increases considerably the resistance
to the forward motion, so that the advantage is not so great
as at first might be thought.

OF GREAT BRITAIN.

It is doubtless owing to tlieir inferiority as projectiles that
the size of bats, and especially insects, never equals that of
birds.

5th — The angle at which the air is attacked (?) and the
angle of favourable fall (a + ?), whose ratio is fixed, are
independent of the weight, increasing with c S' and diminishing
with cS. These angles can be accurately obtained for each

specie, as it only depends upon — — , which evidently varies

c S

little between individuals, whilst P, especially in solitary birds,
shows considerable variations.

6th — For similar flying beings the velocity and the
relative work are proportionate to the square root of the
homologous dimensions, and in this case the number of beats
of the wings, supposing them to be of equal amplitude, is
inversely proportionate to the square root of the dimensions,
which fact has been pointed out by M. Hureau de Villeneuve.
The angles of flight, that is to say the manner of flight, remain
undisturbed.

7th — All our calculations and their results are applicable
to vertical screws whilst hovering, but not when advancing
laterally, for then the movements of the wings relatively to the
air is not uniform. It must be understood that every time the
machine ascends and descends, the force of gravity, useful or
injurious, modifies proportionately the work of the motive power.

8th — The calculations can be applied to all varieties of
inclined planes, provided with propellers like my model aero¬
planes, but if we take into account the efficacy of the propeller,
it will be of advantage to attack the air still more obliquely,
for the thrust of the propeller becoming less its slip will be
reduced.

As the useful work or efficient thrust of the propeller is
divided in a determined ratio between the suspension and the

AERONAUTICAL 80CIETY

forward motion, we see that the thrust is a given multiplicator.
and besides small compared to that necessary for the machine
to cleave the air. We are then led to the following remarkable
theorem.

The area of the propellers must always be proportioned
to resistance of the forward motion c'S' and not to the weight
of the machine, which is also without direct influence upon the
size of the rudders and other auxiliary surfaces. The area is
also independent of the density of the fluid in which the
machine moves and its velocity, which is evident in the propul¬
sion of ships.

Before discovering these laws in 1870 I was puzzled to
know how the flying,- fish was able to sustain itself with its
small pectoral muscles and wings badly formed for beating the
air. These calculations led me to think that the fish (whilst
at the same time taking advantage, as the sea-birds do. of the
current of air ascending along the slopes of the waves) propels
itself not with its wings but its tail. Since then I have had
the pleasure of knowing that these views are entirely confirmed
by the observations of MM. de Tessan and Agassiz.

9th — If the work of translation exceeds half the total work
it increases at first very slowly, and thus aviation, which allows
of compact and spindle-shaped forms, is veritably for moderate
masses the most economical mode of transport for high
velocities, since it is only necessary to cleave the air.

Note — Several of these results, and amongst them those
relating to the propellers, subsist with another law of the
resistance of the air.

IV.

At length our calculations, combined with certain results
of observation, allow us to obtain very nearly the co-efficient
c and c' of resistance to flying bodies, and the angle at which
they attack the air when they glide.

OF 3REAT BRITAIN.

It is also, as we have remarked, true enough of ordinary
flight.

When the raven, for example, is about to alight upon the
ground he ceases to flap his wings and glides with regular
movements till near the ground, which he follows for some
metres whilst he retards his velocity.

I have watched them alight thus in a place surrounded
by high poplars, and noted the time and height when at the
beginning of its descent, and also the place and time where it
touched the ground.

It was only necessary to measure the distance between the
tree and this spot, the height of the branch from which the
bird dropped, in order' to obtain the velocity V and the work
expended per second.

I have made four or five such experiments in calm weather,
which is absolutely necessary if we wish to obtain accurate
results, and I here take the mean of two observations in which
the flight was most horizontal.

It is admitted by theorem II that in this case the work
was equally divided between the translation and the suspension,
for the bird ceases to flap his wings from motives of economy,
and thus should cease them as soon as possible.

I have found, having regard to the height due to the
initial velocity, that the raven descends 4ft. 5in. per second with
a velocity of 86ft. lin. This agrees very well with the obser¬
vations of the late Sir George Cayley.

The mean of a large number of measurements, in the case
of the* ravenj gives for the weight P = 50 5gr. (about 1‘1 libs.),
44c. (about 17^in.), as the length of wing 19*4c. (7§in.), as
the mean width 17c. (6fin.), as the length of tail (from the
roots of the feathers), and 38c. (1 5in.) as the length of the
body (the beak to the commencement of the tail). This last
number, along with the circumference of the body, 28c. (1 lin.),

AERONAUTICAL 80CIETY

gives the projectile form of the bird. The mean thickness of
the wing is about 9mm. (about £in.)

From the above figures the amount of surface exposed by
the bird in the case under consideration would be about
S = Omq., 185, 1500cq. (about 232^ sq. in.), and 350cq-
(about 54in.) for the body and tail.

The inferior surface of the body, owing to its rounded
form, offers little resistance where the air is not retained
laterally by the wings. The tail will only sustain to a moderate
extent, for it is less inclined to the line of flight than the
wings are, as I have shown to be necessary in l' Aeronaute for
January, 1872.

With regard to S' the trunk of the bird is 60cq. (9£ sq. in.),
and the edge of the wings 80cq. (12^ sq. in.), which is a fact
that few persons know I believe.

We thus have S' = Omq. -014, and can now find the
unknown factors, first observing that the ratio of the fall to

the velocity is exactly sine (a + £) = sine 2 ? =

lm 35

11™

= sine 7 °

Whence a = £ = 3° 30. Now the equation cS V4 sine f = P
P

gives c = and the resistance of a surface lmq., in

° S Vs sine * ^

moving at a velocity of lm. at an angle of 10° will be

. P sine 10° „ . , , , . . . 1

c sine 10 = „ = 64gr., which is a third more than

S V2 sine e

had been found by Thibault, which shows the advantage of
using a convenient form and curve. The sea-gull, of which
the wings are narrow, gives, by the same method, a slightly
superior result.

P sine a

Again from c' = — ■ - = 18*5 gr., the raven, thanks to

b V ~

its form, cleaves the air seven times more easily than a flat
surface of the same section. This agrees very well with what

OF great britain

we know of the resistance to ships, which in cases where there
is an analagous relation between the rubbing surface and the
cross section, the friction is, roughly speaking, about half the
resistance. Applying this rule to our raven we have a perception
of the co-efficient of friction F, the surface of the bird, which
is slightly superior to 2 S. We find for the friction of a surface
of lmq., moving at a speed of lm., F = O3ogr. nearly.

This value is plausible.

As all these results are drawn from a few observations
difficult to make, we must not regard them as absolute ; but 1
believe them to be so. I believe them, with the exception of F.
to be exact to within a fifth.

It would be very interesting to collect a large number of
similar data of different flying beings, especially large birds, so
that we could get several means.

If we do not accept the law of the simple sine of the
angle of incidence, we are obliged to renounce that of sine*
generally recognised, since it gives from known tables a fall of
loft. lin. per second to the raven, even when we do not take
into account the translation, whilst, as we have just seen, the
real fall is only 4ft. 5in. The advantage of the oblique is
manifest.

It is thus that the flight of birds, incessantly proving the
resistance of the air, can give us valuable data, and if it does
not replace the result of special experiments, at least it will
guide and light us considerably in the difficult task.

It has been thought judicious to include in these
Annual Reports , as far as space will allow, all
the Literature upon the subject which is worth
re-producing. Ln this category we place the late
Sir George Cayley s recorded experience.

AERONAUTICAL SOCIETY

0 1ST AERIAL NAVIGATIO LT,

Sir GEORGE CAYLEY. Bart.

Reprinted from “ Nicholson x Journal’' for 1809 if 1810.

Since the days of Bishop Wilkins the scheme of flying by
artificial wings has been much ridiculed, and indeed the idea
of attaching wings to the arms of a. man is ridiculous enough,
as the pectoral muscles of a bird occupy more than two-thirds
of its whole muscular strength, whereas in man the muscles
that could operate upon the wings thus attached would probably
not exceed one-tenth of the whole mass. There is no proof
that, weight for weight, a man is comparatively weaker than
a bird ; it is therefore probable, if he can be made to exert his
whole strength advantageously upon a light surface similarly
proportioned to his weight, as that of the wing to the bird,
that he would fly like a bird. The flight of a strong man by
great muscular exertion, though a curious and interesting
circumstance, inasmuch as it will probably be the first means
of ascertaining this power and supplying the basis whereon
to improve, it would be of little use. I feel perfectly confident,
however, that this noble art will soon be brought home to man’s
general convenience, and that we shall be able to transport
ourselves and families, and their goods and chattels, more
securely by air than by water, and with a velocity of from
20 to 100 miles per hour. To produce this effect it is only
necessary to have a first mover, which will generate more power

OF GREAT BRITAIN.

in a given time, in proportion to its weight, than the animal
system of muscles.

The consumption of coal in a Boulton & Watt’s steam
engine is only about 5-^lbs. per hour for the power of one horse.
The heat produced by the combustion of this portion of inflam¬
mable matter is the sole cause of the power generated, but it
is applied through the intervention of a weight of water
expanded into steam, and a still greater weight of cold water f
to condense it again. The engine itself likewise must be
massive enough to resist the whole external pressure of the
atmosphere, and therefore is not applicable to the purpose
proposed. Steam engines have lately been made to operate by
expansion only, and these ‘might be constructed so as to be
light enough for this purpose, provided the usual plan of a
large boiler be given up and the principle of injecting a proper
charge of water into a mass of tubes, forming the cavity for the
fire, be adopted in lieu of it. The strength of vessels to resist
internal pressure being inversely as their diameters, very slight
metallic tubes would be abundantly strong, whereas a large
boiler must be of great substance to resist a strong pressure.
The following estimate will show the probable weight of such
an engine with its charge for one hour : — lbs.

The engine itself ... ... ... ... 90 to 100

. Weight of inflamed cinders in a cavity pre¬
senting about 4ft. surface of tube ... 2f>

Supply of coal for one hour ... ... ... 6

Water for ditto, allowing steam of one atmos¬
phere to be j (i. the specific gravity of
water ... ... ... ... ... 32

163

T do not propose this statement in any other light than

AERONAUTICAL SOCIETY

as a rude approximation to truth, for as the steam is operating
under the disadvantage of atmospheric pressure it must be
raised to a higher temperature than in Messrs. Boulton & Watt's
engine, and this will require more fuel ; but if it take twice as
much still the engine would be sufficiently light, for it would
be exerting a force equal to raising ooOlbs. one foot high per
second, which is equivalent to the labour of six men. whereas
the whole weight does not much exceed that of a man.

It may seem superfluous to enquire further relative to a
first mover for aerial navigation, but lightness is of so much
value in this instance that it is proper to notice the probability
that exists of using the expansion of air, by the sudden com¬
bustion of inflammable powders or fluids, with great advantage.
The French have lately shown the great power produced by
igniting inflammable powders in close vessels, and several years
ago an engine was made to work in this country in a similar
manner by inflammation of spirit of tar. I am not acquainted
with the name of the person who invented this engine, but
from some minutes with which I was favoured by Mr. William
Chapman, of Newcastle, I find that 30 drops of oil of tar raised
8cwt. to the height of 22in. ; hence 1 horse-power would
consume from .10 to 121bs. per hour, and the engine itself
need not exceed 501bs. weight. I am informed by Mr. Chapman
that this engine was exhibited in a working state to Mr. Rennie. .
Mr. Cartwright, and several other gentlemen capable of appre¬
ciating its powers, but that it was given up in consequence of the
expense attending its consumption being about eight times
greater than that of a strain engine of the same power.
Probably a much cheaper engine of this sort might be produced
by a gas-light apparatus and by firing the inflammable air
generated with a due portion of common air under a piston.
Upon some of these principles it is perfectly clear that force
can be obtained by a much lighter apparatus than the muscles

OF GREAT BRITAIN.

of animals or birds, and therefore in such proportion may aerial
vehicles be loaded with inactive matter. Even the expansion
steam engine, doing the work of six men and only weighing
equal to one, will as readily raise five men into the air as one
man can elevate himself by his own exertions, but by increasing
the magnitude of the engine 10, 50, or 500 men may be
equally well conveyed, and convenience alone, regulated by the
strength and size of materials, will point out the limit for the
size of vessels in aerial navigation.

Having rendered the accomplishment of this object
probable upon the general view of the subject, I shall proceed
to point out the principles of the art itself. For the sake of
perspicuity I shall, in the first instance, analyze the most simple
action of the wing in birds, although it necessarily supposes
many previous steps.

When large birds, that have a considerable extent of wing
compared with their weight, have acquired their full velocity,
it may frequently be observed that they extend their wings, and
without waving them continue to skim for some time in a

Fig. 1.

horizontal path. Fig, 1 represents a bird in this act. Let ab
be a section of the plane of both wings opposing the horizontal
current of air (created by its own motion), which may be
represented by the line ad. and is the measure of the velocity

AEBONATTTIOAL SOCIETY

of the bird. The angle bdc can be increased at the will of the
bird, and to preserve a perfectly horizontal path, without the
wing being waved, must continually be increased in a complete
ratio (useless at present to enter into) till the motion is stopped
altogether ; but at one given time the position of the wings
may be truly represented by the angle bdc. Draw de perpen¬
dicular to the plane of the wings, produce the line cd as far as
required, and from the point e, assumed at pleasure in the
line de, let fall ef perpendicular to df ; then de will represent
the whole force of the air under the wing, which being resolved
into the two forces ef and fd the former represents the force
that sustains the weight of the bird, the latter the retarding
force by which the velocity of the motion producing the
current cd will be continually diminished ; ef is always a
known quantity, being equal to the weight of the bird, and
hence fd is also known as it will always bear the same pro¬
portion to the weight of the bird as the sine of the angle bdc
bears to its cosine, the angles def and bdc being equal. In
addition to the retarding force thus received is the direct
resistance which the bulk of the bird opposes to the current.
This is a matter to be entered into separately from the principles
now under consideration, and for the present may be wholly
neglected under the supposition of its being balanced by a
force precisely equal and opposite to itself.

Before it is possible to apply this basis of the principle of
flying in birds to the purpose of aerial navigation it will be
necessary to encumber it with a few practical observations.

The whole problem is confined within these limits, viz. —
To make a surface support a given weight by the application
of power to the resistance of air. Magnitude is the first
question respecting the surface. Many experiments have been
made upon the direct resistance of air by Mr. Robins, Mr. Rouse.
Mr. Edgeworth, Mr. Smeaton, and others. The result of

OF GREAT BRITAIN,

Mr. Smeaton’s experiments and observations was that a surface
of a square foot met with a resistance of lib. when it travelled
perpendicularly to itself through air at a velocity of 21ft.
per second. I have tried many experiments upon a large scale
to ascertain this point. The instrument was similar to that
used by Mr. Robins, but the surface used was larger, being an
exact square foot, moving round upon an arm- about 5ft. long, and
turned by weights over a pulley. The time was measured by a
stop-watch, and the distance travelled over in each experiment
was 600ft. I shall only give the results of many carefully-
repeated experiments, which are, that a velocity of ll*538ft.
per second generated a resistance of 4oz., and that a velocity
of 17-1 6ft. per second gave 8oz. resistance. This delicate
instrument would have been strained by the additional weight
necessary to have tried the velocity generating a pressure of
lib. per square foot ; but if the resistance be taken to vary as
the square of velocity, the former will give the velocity necessary
for this purpose at 23‘lft., the latter 24'28ft. per second.
I shall therefore take 23 • 6ft. as somewhat approaching the
truth.

Having ascertained this point, had our tables of angular
resistance been complete, the size of the surface necessary for
any given weight would easily have been determined. Theory,
which gives the resistance of a surface opposed to the same
current in different angles, to be as the square of the sine
of the angle of incidence, is of no use in this case, as it appears,
from the experiments of the French Academy, that in acute
angles the resistance varies much more nearly in the direct
ratio of the sines than as the squares of the sines of the angle
of incidence. The flight of birds will prove to an attentive
observer that, with a concave wing apparently parallel to the
horizontal path of the bird, the same support and, of course,
resistance is obtained ; and hence I am inclined to suspect that

AERONAUTICAL SOCIETY

under extremely acute angles, with concave surfaces, the
resistance is nearly similar in them all. I conceive tho operation
may be of a different nature from what takes place in larger
angles, and may partake more of the principle of pressure
exhibited in the instrument known by the name of the hydros¬
tatic paradox. A slender filament of the current is constantly
received under the anterior edge of the surface and directed
upward into the cavity by the filament above it being obliged
to mount along the convexity of the surface, having created a
slight vacuity immediately behind the point of separation.
The fluid accumulated thus within the cavity has to make its
escape at the posterior edge of the surface where it is directed
considerably downward, and therefore has to overcome and
displace a portion of the direct current passing with its full
velocity immediately below it ; hence whatever elasticity this
effort requires operates upon the whole concavity of the surface,
excepting a small portion of the anterior edge. This may or
may not be the true theory, but it appears to me to be the
most probable account of a phenomenon which the flight of
birds proves to exist.

Six degrees was the most acute angle, the resistance of
which was determined by the valuable experiments of the
French Academy, and it gave ^ ot the resistance which the
same surface would have received from the same current when
perpendicular to itself. Hence, then, a superficial foot, forming
an angle of six degrees with the horizon, would, if carried
forward horizontally (as a bird in the act of skimming) with a
velocity. of 23’ 6ft. per second, receive a pressure of T4<y of a pound
perpendicular to itself ; and if we allow the resistance to
increase as the square of the velocity at 27-3ft. per second, it
would receive a pressure of lib. I have weighed and measured
the surface of a great many birds, but at present shall select
the common rook, because its surface and weight are as nearly

OF GREAT BRITAIN.

fi7

as possible in the ratio of a superficial foot to a pound The
flight of this bird, during any part of which they can skim at
pleasure, is (from an average of many observations) about
34'5ft. per second. The concavity of the wing may account
for the greater resistance here received than the experiments
upon plane surfaces would indicate. I am convinced that the
angle made use of in the crow’s wing is much more acute than
6 degrees ; but in the observations that will be grounded upon
these data I may safely state that every foot of such curved
surface, as will be used in aerial navigation, will receive a
resistance of lib. perpendicular to itself when carried through
the air in an angle of 6 degrees with the line of its path at a
velocity of about 34 to 35ft. per second.

Fig. 2.

Let ab, Fig. 2, represent such a surface or sail made of
thin cloth, and containing about 200 square feet (if of a square
form the side will be a little more than 14ft.), and the whole
of a firm texture. Let the weight of the man and the machine
be 2001bs. Then if a current of wind blew in the direction cd
with a velocity of 35ft. per second, at the same time that a cord,
represented by cd, would sustain a tension of 2 libs., the machine
would be suspended in the air. or at least be within a few ounoes

AfiBONAlTTIOAIi SOCIETY

of it (falling short of such support cnly in the ratio of the sine
of the angle of 94 degrees compared with the radius, to balance
which defect suppose a little ballast to be thrown out), for the
line de represents a force of 2001bs., which, as before being
resolved into df and fe, the former will represent the resistance
in the .direction of the current, and the latter that which
sustains the weight of the machine. It is perfectly indifferent
whether the wind blow against the plane or the plane be driven
with an equal velocity against the air. Hence if this machine
were pulled along by a cord, cd, with a tension of about 211bB„
at a velocity of 35ft. per second, it would be suspended in a
horizontal path ; and if, in lieu of this cord, any other pro¬
pelling power were generated in this direction, with a like
intensity, a similar effect would be produced. If therefore the
waft of surfaces advantageously moved by any force generated
within the machine took place to the extent required, aerial
navigation would be accomplished. As the acuteness of the
angle between the plane and current increases, the propelling
power required is less and less. The principle is similar to that
of the inclined plane, in which, theoretically, lib. may be made
to sustain all but an infinite quantity, for in this case if the
magnitude of the surfaces be increased ad infinitum, the angle
with the current may be diminished, and consequently the
propelling force in the same ratio. In practice the extra
resistance of the car and other parts of the machine, which
consume a considerable portion of power, will regulate the
limits to which this principle, which is the true basis of aerial
navigation, can be carried, and the perfect ease with which
some birds are suspended in long horizontal flights, without one
waft of their wings, encourages the idea that a slight power
only is required.

I have myself made a large machine on this principle,
large enough for aerial navigation, but which I have not had

OF 3EEAT BRITAIN.

an opportunity to try the effect of, excepting as to its proper
balance and security. It was beautiful to see this noble white
bird, sail majestically from the top of a hill to any given point
of the plane below it with perfect steadiness and safety,
according to the set of its rudder, merely by its own weight
descending in an angle of about 8 degrees with the horizon.

As it may be amusing to some of my readers to see a
machine rise in the air by mechanical means, the following is
a description of one of which any one can construct at the

Fig. 3.

expense of ten minutes labour : — a and b. I ig. 8, are two corks,
into each of which arc inserted four wing feathers, from any
bird, so as to be slightly inclined like the sails of a windmill,
but in opposite directions in each set. A round shaft is fixed

7<»

A 6 KON A l' TIC Al. SOC1 1ST \

in the cork n. which ends in a sharp point. At the upper part
ot the cork h is fixed a whalebone bow. having a small pivot
hole in its centre to receive the point of the shaft. The bow
is then to be strung equally on each side to the upper portion
of the shaft, and the little machine is completed. Wind up the
string by turning the flyers different ways, so that the spring
of the bow may unwind them with their anterior edges
ascending. Then place the cork with the bow attached to it
upon a table, and. with the finger on the upper cork press strong
enough to prevent the string unwinding and taking it away
suddenly, the machine will rise to the ceiling. This was the
first experiment I made upon this subject in the year 1796.

If in lieu of these small feathers large planes, containing
together 200 square feet, were similarly placed, or in any other
more convenient position, and were turned bv a man or first
mover of adequate power, a similar effect would be the conse¬
quence. and for the mere purpose of ascent this is perhaps the
best apparatus : but speed is the great object of this invention,
and this requires a different structure.

In lieu of applying the continued action of the inclined
plane, by means of the rotative motion of flyers, the same
principle may be made use of by the alternative motion of
surfaces backward and forward, as in the following manner : —

Fig. A.

OF GREAT BRITAIN.

Let a and b. Fig. 4, be two surfaces or parachutes supported
upon the long shafts c and d, which are fixed to the ends of
the connecting beam e by hinges. At e let there be a con¬
venient seat for the aeronaut, and before him a cross-bar
turning upon a pivot in the centre, which, being connected
with the shafts of the parachute by the rods / and rj, will
enable him to work them alternately backwards and forwards,
as represented by the dotted lines. If the upright shaft be
elastic or have a hinge to give way a little, near their tops, the
weight and resistance of the parachute will incline them so as
to make a small angle with the direction of their motion, and
hence the machine rises. A slight heeling of the parachute
towards one side, or an alteration in the position of the weight,
may enable the aeronaut to steer such an apparatus tolerably
well ; but many better constructions may be formed for com¬
bining the requisites of speed, convenience, and steerage.

Having described the general principle of support in
aerial- navigation, I shall proceed to show how this principle
must be applied so as to be steady and manageable. Several
persons have ventured to descend from balloons in a parachute
which exactly resembles a large umbrella, with a light car
suspended by cords underneath it. It is very remarkable that
the only machines of this sort which have been constructed
are nearly of the worst possibly form for producing a steady
descent — the purpose for which they are intended. To render
this subject more familiar let us recollect that in a boat
swimming upon water its stability or stiffness depends, in
general terms, upon the weight and distance from the centre
of the section elevated above the water, by any given heel of
the boat on one side ; and on the bulk and its distance from
the centre, which is immersed below the water on the other
side, the combined endeavour of the one to fall and the other
to swim produces the desired effect in a well-constructed boat.

AERONAUTICAL society

The centre of gravity of the boat being more or less below the
centre of suspension is an additional cause of its stability.

Let us now examine the effect of a parachute represented

Fig. 5.

by ab, Fig. 5. When it has heeled into the position represented
by the dotted lines, a is become perpendicular to the current
created by the descent, and therefore resists with its greatest
power ; whereas the side b is become more oblique, and of course
its resistance is much diminished. Hence, so far as this form of
the sail or plane is regarded, it operates directly in opposition to
the principle of stability, for the side that is required to fall resists
much more in its new position, and that which is required to
rise resists much less ; therefore complete inversion would be
the consequence if it were not for the weight being suspended
so very much below the surface, which, counteracting this
tendency, converts the effort into a violent oscillation.

OF GREAT BRITAIN.

On the contrary, let the surface be applied in the inverted

Fig. 6.

position as represented at cd, Fig. 6, and suppose it to be heeled
to the same angle as before represented by the dotted lines cd.
Here the exact inverse of the former instance takes place, for
that side which is required to rise has gained resistance by its
new position, and that which is required to sink has lost it ; so
that as much power operates to restore the equilibrium in this
case as tended to destroy it in the other, the operation very
much resembling what takes place in the common boat. This
angular form, with apex downwards, is the chief basis of
stability in aerial navigation ; but as the sheet which is to
suspend the weight attached to it in its horizontal path through
the air must present a slightly concave surface in a small angle
with the current, this principle can only be used in the lateral

AERONAUTICAL SOCIETY

extension ot the sheet, and this most effectually prevents any
rolling of the machine from side to side. Hence the section
of the inverted parachute, Fig. 6, may equally well represent
the cross section of a sheet for aerial navigation. The principle
ol stability in the direction of the path of the machine must
be derived from a different source.

Fig. 7.

Let nb, Fig. 7, be a longitudinal section of a sail, and
let r b<-' its centre of resistance, which experiment shows to be
considerably more forward than the centre of the sail. Let cd
be drawn perpendicular to nb, and let the centre of gravity of
the machine be at any point in that line as at d. ; then if it be
projected in a horizontal path, with velocity enough to support
the weight, the machine will retain its relative position like a
bird in the act of skimming, for drawing ce perpendicular to
the horizon, and de parallel to it, the line ce will, at some
particular moment, represent the supporting power and likewise
its opponent, the weight ; and the line de will represent the
retarding power and its equivalent, that portion of the pro¬
jectile force expended’ in overcoming it ; hence, these various
powers being exactly balanced, there is no tendency in the
machine but to proceed in its path with its remaining portion,
of projectile force.

v*l" UKKAT UKITAIN

l • >

The stability in this position, arising from the centre of
gravity being below the point of suspension, is aided by a
remarkable circumstance that experiment alone could point out.
In very acute angles with the current it appears that the
centre of resistance in a sail does not coincide with the centre of
its surface, but is considerably in front of it. As the obliquity
of the current decreases these centres approach and coincide
when the current becomes perpendicular to the sail. Hence
any heel of the machine backward or forward removes the
centre of support behind or before the point of suspension, and
operates to restore the original position by a power equal to
the whole weight of the machine, acting upon a lever equal in
length to the distance the centre has removed.

To render the machine perfectly steady, and likewise to
enable it to ascend and descend in its path, it becomes necessary
to add a rudder in a similar position to the tail in the bird.
Lot f<j be the section of such a surface parallel to the current
and let it be capable of moving up and down upon // as a
centre, and of being fixed in any position. The powers of the
machine being previously balanced, if the least pressure be
exerted by the current either upon the upper or under surface
of the rudder, according to the will of the aeronaut, it will
cause the machine to rise or fall in its path so long as the
propelling force is continued with sufficient energy.

From a variety of experiments upon this subject I find
that when the machine is going forward, with a superabundant
velocity, or that which would induce it to rise in its path, a
very steady horizontal course is effected by a considerable
depression of the rudder, which has the advantage of making
use of this portion of sail in aiding the support of the weight.
When the velocity is becoming less, as in the act of alighting,
then the rudder must gradually recede from this position and
even become elevated for the purpose of preventing the machin*

AERONAUTICAL SOCIETY

from sinking too much in front, owing to the combined effect
of the want of projectile force sufficient to sustain the centre of
gravity in its usual position, and of the centre of support
approaching the centre of the sail.

The elevation and depression of the machine are not the
only purposes for which the rudder is designed. This ap¬
pendage must be furnished with a vertical sail and be capable
of turning from side to side in addition to its other movements,
which effects the complete steerage of the vessel.

All these principles upon which the support, steadiness,
elevation, depression, and steerage of vessels for aerial navi¬
gation depend have been abundantly verified by experiments
both upon a large and small scale. I made a machine having
a surface of 300 square feet, which was accidently broken
before there was an opportunity of trying the effect of the
propelling apparatus, but its steerage and steadiness were
perfectly proved, and it would sail obliquely downwards in any
direction according to the set of the rudder. Its weight was
561bs., and it was loaded with 841bs., thus making a total of
1401bs., about 2 square feet to lib. Even in this state, when
any person ran forward in it with his full speed, taking
advantage of a gentle breeze in front, it would bear upward so
strongly as scarcely to allow him to touch the ground, and
would frequently lift him up and convey him several yards
together.

The best mode of producing the propelling power is the
only thing that remains yet untried towards the completion of
the invention. I am preparing to resume my experiments upon
this subject, and state the following observations in the hope
that others may be induced to give their attention towards
expediting the attainment of this art.

The act of flying is continually exhibited to our view, and
the principles upon which it is effected are the same as those

OF GREAT BRITAIN.

before stated. If an attentive observer examines the waft of
a wing he will perceive that about one-third part towards the
extreme point is turned obliquely backward, this being the only
portion that has velocity enough to overtake the current
passing so rapidly beneath it when in this unfavourable position.
Hence this is the only portion that gives any propelling force.

Fig. 8.

. To make this more intelligible let ah. Fig. 8, be a section
of this part of the wing. Let cd represent the velocity of the
bird’s path or the current, and ed that of the wing in its waft ;
then ce will represent the magnitude and direction of the com¬
pound or actual current striking the under surface of the wing.
Suppose ef, perpendicular to ab, to represent the whole pressure ;
ey, being parallel to the horizon, will represent the propelling
force, and yf, perpendicular to it, the supporting power. A
bird is supported as effectually during the return as during the
beat of its wing. This is chiefly effected by receiving the

AERONAUTICAL HOCIETT

resistance of the current under that portion of the wing next
the body, where its receding motion is so slow as to be of
scarcely any effect. The extreme portion of the wing, owing
to its velocity, receives a pressure downward and obliquely
forward, which forms part of the propelling force, and at the
same time by forcing the hinder part of the middle portion of
the wing downward, so increases its angle with the current as
to enable it still to receive nearly its usual pressure from
beneath.

As the common rook has its surface and weight in the
ratio of a square foot to the lb., it may be considered as a
standard for calculation of this sort ; and I shall therefore
state, from the average of many careful observations, the move¬
ments of that bird. Its velocity, represented by cd, Fig. 8, is
34*f>ft. per second. It moves its wing up and down once in
living over a space of 1 2.9ft. Hence, as the centre of resistance
of the extreme portion of the wing moves over a space of 075
of a foot each beat or return, its velocity is about 4ft. per
second, represented by the line ed. As the wing certainly
overtakes the current it. must be inclined from it at an angle
something less than 7°, for at this angle it would scarcely be
able to keep parallel with it unless the waft downward was
performed with more velocity than the return, which may be.
and probably is. the case, though these movements appear of
equal duration.

The propelling power represented by ,></ under these
circumstances cannot be equal to part of the supporting
power gf exerted upon this portion of the wing, yet this,
together with the aid from the return stroke, has to overcome
all the retarding power of the surface and the direct resistance
occasioned by the bulk of the bird.

It has been before suggested, and I believe upon good
grounds, that very acute angles vary little in the degree of

OF GREAT BRITAIN.

resistance they make under a similar velocity of current.
Hence it is probable that this propelling part of the wing
receives little more than its common proportion of resistance
during the waft downward. If it be taken at one-third of the
whole surface, and one-eighth of this be allowed as the
propelling power, it will only amount to ^ of the weight
of the bird, and even this is exerted only half the duration of
the flight. The power gained in the return of the wing must
be added to render this statement correct, and it is difficult to
estimate this ; yet the following statement proves that a greater
degree of propelling force is obtained upon the whole than the
foregoing observations will justify.

Suppose the largest circle that can be described in the
breast of a crow to be 12in. in area : such a surface moving
at a velocity of 34 ‘5ft. per second would meet a resistance of
0-216 of a lb., which, reduced by the proportion of the
resistance of a sphere to its great circle (given by Mr. Robins
as 1 to 2’27), leaves a resistance of 0-095 of a lb. had the
breast been hemispherical. It is probable, however, that the
curve made use of by nature to avoid resistance being so
exquisitely adapted to its purpose will reduce this quantity to
one half less than the resistance of the sphere, which would
ultimately leave 0*0475 of a lb. as somewhat approaching the
true resistance. Unless, therefore, the return 6f the wing gives
a greater degree of propelling force than the beat, which is
improbable, no such resistance of the body could be sustained.
Hence, though the eye cannot perceive any distinction between
the velocities of the beat and return of the wing, it probably
exists, and experiment alone can determine the proper ratio
between them.

From these observations we may, however, be justified in
the remark that the act of flying requires less exertion than
from the appearance is supposed.

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Not having sufficient data to ascertain the exact degree
of propelling power exerted by birds in the act of flying, it is
uncertain what degree of energy may be required in this
respect for vessels for aerial navigation ; yet when we consider
the many hundred miles of continued flight exerted by birds
of passage, the idea of its being only a small effort is greatly
corroborated. To apply the power of the first mover to the
greatest advantage in producing this effect is a very material
point. The mode universally adopted by nature is the oblique
waft of the wing. We have only to choose between the direct
beat overtaking the velocity of the current, like the oar of a
boat, or one applied like the wing, in some assigned degree of
obliquity to it. Suppose 35ft. per second to be the velocity of
an aerial vehicle, the oar must be moved with this speed
previous to its being able to receive any resistance ; then if it
be only required to obtain a pressure of of a lb. upon each
square foot it must exceed the velocity of the current 7*5ft.
per second. Hence its whole velocity must be 42 *5ft. per
second. Should the same surface be wafted downward like a
wing, with the hinder edge inclined upward in an angle of
about 50-40° to the current, it will overtake it at a velocity of
3*5ft. per second ; and as a slight unknown angle of resistance
generates a lb. pressure per square foot at the velocity, probably
a waft of little more than 4ft. per second would produce this
effect, one-tenth part of which would be the propelling power.
The advantage in favour of this mode of application, compared
with the former, is rather more than ten to one.

In continuing the general principles of aerial navigation,
for the practice of the art. many mechanical difficulties present
themselves winch require a considerable course of skilfully-
applied experiments before they can be overcome ; but, to a
certain extent, the air has already been made navigable, and
no one who has seen the steadiness with which weights, to the

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amount of ten stone (including four stone, the weight of the
machine), hover in the air. can doubt of the ultimate accom¬
plishment of this object.

The first impediment I shall take notice of is the great
power that must be exerted previous to the machine’s acquiring
that velocity which gives support upon the principle of the
inclined plane, together with the total want of all support
during the return of any surface used like a wing. Many
birds, and particularly water fowl, run and flap their wings for
several yards before they gain support from the air. The
swift ( hiraudo apus. Lin.) is not able to elevate itself from
level ground. The inconvenience under consideration arises
from very different causes in these two instances. The sup¬
portive surface of most swimming birds does not exceed the
ratio of four-tenths of a square foot to every lb. of their weight.
The swift, though it scarcely weighs an ounce, measures 18in.
in extent of wing. The want of surface in the one case and the
inconvenient length of wing in the other oblige these birds to
aid the commencement, of their flight by other expedients, yet
they can both fly with great power when they have acquired
this full velocity.

A second difficulty in aerial navigation arises from the
great extent of lever which is constantly operating against the
first mover in consequence of the distance of the centre of
support in large surfaces, if applied in the manner of wings.

A third and general obstacle is the mechanical skill
required to unite great extension of surface with strength and
lightness of structure, at the same time having a firm and
steady movement in its working parts, without exposing
unnecessary obstacles to the resistance of the air. The first
of these obstacles that have been enumerated operates much
more powerfully against aerial navigation upon a large scale
than against birds, because the small extent of their wings

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obliges them to employ a very rapid succession of strokes in
order to acquire that velocity which will give support, and
during the small interval of the return of the wing this weight
is still rising, as in a leap, by the impulse of one stroke till it
is again aided by another. The large surfaces that aerial
navigation will probably require, though necessarily moved with
the same velocity, will have a proportionately longer duration
both of the beat and return of the wing, and hence a greater
descent will take place during the latter action than can be
overcome by the former.

There appears to be several ways of obviating this
difficulty. There may be two surfaces, each capable of sus¬
taining weight, and placed one above the other, having such a
construction as to work up and down in opposition when they
are moved, so that one is always ready to descend the moment
the other ceases. These surfaces may be so made, by a valve¬
like structure, as to give no opposition in rising up, and only to
resist in descent. The action may be considered either oblique,
as in rotative flyers, alternately so, without any up-and-down
waft as in the engine I have described at Fig. 12, a number
of small wings in lieu of large ones, upon the principle of the
flight of birds, with small intervals of time between each waft,
and, lastly, by making use of light wheels to preserve the
propelling power, both of the beat and the return of the wings,
till it accumulates sufficiently to elevate the machine upon the
principle of those birds which run themselves up. This action
might be aided by making choice of a descending ground like
the swift.

With regard to another part of the first obstacle I have
mentioned, viz., — the absolute quantity of power demanded
being so much greater at first than when the full velocity has
been acquired, — it may be observed that, in the case of human
muscular strength being made use of. a man can exert, for a

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tew seconds, a surprising degree of force. He can run upstairs
for instance with a velocity of from 0 to 8ft.. perpendicular
height, per second, without any dangerous effort. Here the
muscles of his legs only are in action, but. for the sake of
making a moderate statement, suppose that with the activity
of his amis and body, in addition to that of his legs, he is
equal to l’ising his weight 8ft. per second ; if in this case he
weighs 11 stone, or 1541bs.. he will be exerting for the time,
and energy equal to. more than the ordinary force of two of
Messrs. Boulton & Watt's steam horses, and certainly more
than twelve men can bestow upon their constant labour. If
expansive first movers be made use of they may be so con¬
structed as to be capable of doing more than their constant
work, or their power may be made to accumulate for a few
moments by the formation of a vacuum or the condensation of
air, so that these expedients may restore at one time, in
addition to the working of the engine, that which they had
previously absorbed from it.

With regard to the second obstacle in the way of aerial
navigation, viz.. — the length of leverage to which large wing¬
like surfaces are exposed. — it may be observed that being a
constant and invariable quality, arising from the degree of
support such surfaces give, estimated at their centres of
resistance, it may be balanced by an elastic agent that is so
placed as to oppose it.

Fig. 9.

Let a and b, Fig. 9. be two wings of an aerial vehicle in

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the act of skimming, then half the weight of the vessel is
supported from the centre of resistance of each wing, as
represented by the arrows under them. If the shorter ends of
these levers be connected by cords to the string of a bow c,
of sufficient power to balance the weight of the machine at
the points a and b, then the moving power will be left at full
liberty to produce the waft necessary to bend up the hinder
edge of the wing and gain the propelling power. A bow is not
in fact an equable spring, but may be made so by using a spiral
fusee. I have made use of it in this place merely as the most
simple mode of stating the principles I wished to exhibit.
Should a counter-balancing spring of this kind be adopted in
the practice of aerial navigation, a small well-polished cylinder,
furnished with what may be termed a bag-piston (upon the
principle made use of by nature in preventing the return of
blood to the breast, when it has been driven into the aorta by
the intervention of the semilunar valves), would, by a vacuum
being excited each stroke of the wing, produce the desired
effect, with scarcely any loss of friction. I have made use of
several of these pistons, and have no scruple in asserting that,
for all blowing engines, even friction is an evil, and being very
nearly air-tight is sufficient. There is no piston at all com¬
parable with them. The most irregular cylinder with a piston
of this kind will act with surprising effect. To give an
instance : a cylinder of sheet-tin, 8in. long and 3-^in. in
diameter, required 41bs. to force the piston down in 15 minutes,
and in other trials became perfectly tight in some positions,
and would proceed no farther. The friction, when the cylinder
was open at both ends, did not exceed half-an-ounce. These
elastic agents may likewise be useful in gradually stopping the
momentum of large surfaces when used in any alternate
motion, and in thus restoring it during their return.

Another principle that may be applied to obviate this

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leverage of a wing is that of using such a construction as will
make the supporting power of the air counter-balance itself.
It has been before observed that only about one-third of the
wing in birds is applied in producing the propelling power, the
remainder, not having velocity sufficient for this purpose, is
employed in giving support both in the beat and return of the
wing.

Fig. 10.

Let a and b, Fig. 10, be two wings continued beyond
the pole or hinge upon which they turn at c. If the extreme
parts at a and b be long and narrow they may be balanced,
when in the act of skimming, by a broad extension of less
length on their opposite side, this broad extension, like the
lower part of the wing, will always give nearly the same
support, and the propelling part of the surface will be at
liberty to act unincumbered by the leverage of its supporting
power. This plan may be modified many different ways, but
my intention, as in the fonner case, is still the principle in its
simplest form.

A third principle upon which the leverage of a surface
may be prevented is by giving it a motion parallel to itself,
either directly up and down or obliquely so. The surface al.

A KRON AUT1CAL SOCIETY

81,

Fig. 11.

Fig. 11, may be moved perpendicularly by the shaft which
supports it down to the position kc. or if it be supported upon
two shafts, with hinges at d and c. it may be moved obliquely
parallel to itself into the position hi.

A fourth principle upon which the leverage may be greatly
avoided, when only one hinge is used, is by placing it consider¬
ably below the plane of the wing, as at the point d, Fig. 11.
in respect to the surface a. It may be observed in the heron,
which is a weak bird with an extended surface, that its wings
curve downward considerably from the hinge to the tip ; hence
the extreme portion which receives the chief part of the stroke
is applied obliquely to the current it creates, and thus evades,
in a similar degree, the leverage of that portion of the sup¬
portive power which is connected with the propelling power.
These birds seldom carry their waft much below the level of
the hinge of the wing, where this principle, so far as respects
the supporting power, would vanish.

By making use of two shafts of unequal length the two
last-mentioned principles may be blended to any required
extent. Suppose one hinge to be at f and the other at //,
Fig. 11, then the surface, at the extent of its beat, would be
in the position of the line hm. If the surface al, Fig. 11, be
supported only upon one shaft ue, be capable of being forced
in some degree from its rectangular position in respect to the

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shaft, and be concave instead of flat, as here represented, then
the waft may be used alternately backward and forward,
according to the principles of the machine I have described at
Fig. 12. This construction combines the principles of counter¬
poising the supporting power of one part of the surface by that
of an opposite part when the machine is in the act of skimming,
and likewise the advantages of the low hinge, with the
principle of leaving little or no interval without support.

A fifth mode of avoiding leverage is by using the continued
action of oblique horizontal flyers, or an alternate action of the
same kind, with surfaces so constructed as to accommodate
their position to such alternate motion, the hinge or joint being
in these cases vertical. In the construction of large vessels for
aerial navigation a considerable portion of fixed sail will
probably be used, and no more surface will be allotted towards
gaining the propelling power than what is barely necessary,
with the extreme temporary exertion of the first mover, to
elevate the machine and commence the flight. In this case
the leverage of the fixed surface is done away.

The general difficulties of structure in aerial vehicles
(arising from the extension, lightness, and strength required in
them, together with great firmness in the working parts, and
at the same time such an arrangement as exposes no unnecessary
obstacles to the current) I cannot better explain than by
describing a wing which has been constructed with a view
to overcome them.

Fig. 12 represents the shape of the cloth, with a per¬
spective view of the poles upon which it is stretched with
perfect tightness. Upon the point where the rods a and b
intersect is erected an oval shaft, embracing the two cross
poles by a slender iron fork, for the purpose of preserving their
strength uninjured by boring. To this shaft are braced the
ends of the pole b, so as to give this pole any required degree

AERONAUTICAL SOCIETY

Figs. 12 and 13.

of curvature. The pole a is strung like a common bow to the
same curve as the pole b. and is only connected with the
upright shaft by what may be called a check brace, which
will allow the hinder end of this pole to heel back to a certain
extent, but not the fore end. The short brace producing this
effect is shown in Fig. 12. Fig. Id exhibits the fellow wing
to that represented in Fig. 12 erected upon a beam, to which
it is braced so as to convert the whole length of it into a hinge.
The four braces coming from the ends of this beam are shown :
two of them terminate near the top of the centre of the other
shaft, the others are inserted into the point c, Fig. 12, of the
tending rod. A slight bow. not more than three-eighths of an

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inch thick, properly curved by its string and inserted between
the hinder end of the pole a and the curved pole c. completes
the wing.

This fabric contained 54 square feet and weighed only
1 libs. Although both these wings together did not compose
more than half the surface necessary for the support of a man in
the air, yet during their waft they lifted the weight of 9 stone.
The hinder edge, as is evident from the construction, being
capable of giving way to the resistance of the air, any degree
of obliquity, for the purpose of a propelling power, may be used.

I am more particular in describing this wing because it
exemplifies almost all the principles that can be resorted to in the
construction of surfaces for aerial navigation. Diagonal bracing
is the great, principle for producing strength without accumu¬
lating weight, and if performed by thin wires looped at their
ends, so as to receive several laps of cordage, produces but a
trifling resistance in the air and keeps tight in all weather.
When bracings are well applied, they make the poles to which
they are attached bear endwise. The hollow form of the quill in
birds is a very admirable structure for lightness combined with
strength where external bracings cannot be had, a tube being
the best application of matter to resist as a lever ; but the
principle of bracing is so effectual that if properly applied it
will ‘abundantly make up for the clumsiness of human invention
in other respects : and should we combine both these principles,
and give diagonal bracing to the tubular bamboo cane, surfaces
might be constructed with a greater degree of strength and
lightness than any made use of in the wings of birds.

The surface of a heron’s wing is in the ratio of 7 square
feet to a lb. Hence, according to this proportion of wing of
51 square feet, it would weigh about 7flbs. On the contrary,
the wings of water fowl are so much heavier that a surface of
51 square feet, according to their structure, will weigh 18-|lbs.

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I have, in these instances, quoted nearly the extreme cases
amongst British birds ; the wing I have described may there¬
fore be considered as nearly of the same weight in proportion
to its bulk as that of most birds.

Another principle exhibited in this wing is that of the
poles being couched within the cloth so as to avoid resistance.
This is accomplished by the convexity of the frame and the
excessive lightness of the cloth. The poles are not allowed to
form the edge of the wing, excepting at the extreme point of
the bow, where it is very thin, and also oblique to the current.
The thick part of this pole is purposely conveyed considerably
within the edge. In birds a membrane covered with feathers
is stretched before the thick part of the bone of the wing, in a
similar manner and for the same purpose. The edge of the
surface is thus reduced to a thickness of a small cord that is
sewn to the cloth, and gives out loops whenever any fastening
is required. The upright shaft is the only part that opposes
much direct resistance to the current, and this is obviated in a
great degree by a flat oval shape having its longest axis parallel
to the current.

The joint or hinge of this wing acts with great firmness
in consequence of its being supported by bracings to the line
of its axis, and at a considerable distance from each other ; in
fact the bracings form the hinge.

The means of communicating motion to any surfaces
must vary so much, according to the general structure of the
whole machine, that I shall only observe at present that where
human muscular action is employed the movement should be
similar to the mode of pulling oars, from which any other
required motion may be derived. The foot-board in front
enables a man to exert his full force in this position. The
wings I have described were wafted in this manner, and when
they lifted, with a power of 9 stone, not half of the blow

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which a man’s strength could have given was exerted, in con¬
sequence of the velocity required being greater than convenient
under the circumstances. Had these wings been intended for
elevating the person who worked them, they should have
contained from 1 00 to 150 square feet each, but they were
constructed for the purpose of an experiment relative to the
propelling power only.

Avoiding direct resistance is the next general principle
that is necessary to discuss. Let it be remembered, as a
maxim in the art of aerial navigation, that every lb. of direct
resistance that is done away will support oOlbs. of additional
weight without any additional power. The figure of a man
seems but ill calculated to pass with ease through the air. yet
I hope to prove him to the full as well-made, in this respect,
as the crow, which has hitherto been one standard of com¬
parison. paradoxical as it may appear.

The principle that surfaces of similar bodies increase only
as the squares of their homologous lines, while their weights,
or rather solid contents, increase as the cubes of those lines,
furnishes the solution. This principle is unanimously in favour
of large bodies. The largest circle that can be described in a
crow's breast is about 12 square inches in area. If a man
exposes a direct bulk of (1 square feet the ratio of their surfaces
will be as 1 to 72. but the ratio of their weight is as 1 to 110.
which is 1^ to lin. in favour of the man, provided he were
within a case as well-constructed for evading resistance as the
body of the crow : but even supposing him to be exposed in
his natural cylindric shape, in the foreshortened posture of
sitting to work his oars, he will probably receive less resistance
than the crow.

It is of great importance to this art to ascertain the real
solid of least resistance when the length or breadth is limited.
Sir Isaac Newton's beautiful theorem upon this subject is of

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no practical use. as it supposes each particle of the fluid, after
having struck the solid, to have free egress ; making the angles
of incidence and reflection equal. Particles of light seem to
possess this power, and the theory will be true in that case ;
but in the air the action is more like an accumulation of
particles, rushing up against each other in consequence of those
in contact with the body being retarded.

The importance of this subject is not less than the
difficulties it presents. It affects the present interests of
society in its relation to the time occupied in the voyages of
ships. It will still have more effect when aerial navigation,
now in its cradle, is brought home to the uses of man. I shall
state a few crude hints upon this point, to which my subject
has so unavoidably led, and on which I am so much interested,
and shall be glad if in so doing I may excite the attention of
those who are competent to an undertaking greatly beyond my
grasp.

Perhaps some approach toward ascertaining the actual
solid of least resistance may be derived from treating the
subject in a manner something similar to the following : —
Admit that such a solid is already attained, the length and
width being necessarily taken at pleasure. Conceive the
current intercepted or disturbed by the largest circle that can
be drawn within the given spindle, to be divided into concentric
tubular laminae of equal thickness. At whatever distance from
this great circle the apex of the spindle commences on all sides
of this point the central lamina will be reflected in diverging
pencils, or rather an expending ring, making their angles of
incidence and reflection equal. After this reflection they rush
against the second lamina and displace it. This second lamina
contains three times more fluid than the first; consequently
each pencil in the first meets three pencils in the second, and
their direction after the union will be one-fourth of the angle

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with respect to the axis which the first reflection created. In
this direction these two laminae proceed till they are themselves
reflected, when they (considered as one lamina of large di¬
mensions) rush against the third and fourth, which together
contain three times the fluid in the two former laminae, and
thus reduce the direction of the combined mass to one-fourth
of the angle between the axis and the line of the second
reflection. This process is constant, whatever be the angles
formed between the surface of the actual solid of least resistance
at these points of reflection and the directions of the currents
thus reflected.

From this mode of reasoning, which must in some degree
resemble what takes place, and which I only propose as a
resemblance, it appears, that the fluid keeps creeping along the
curved surface of such a solid, meeting it in very acute angles.
Hence, as the experiments of the French Academy show that
the difference of resistance between the direct impulse and that
in an angle of six degrees, on the same surface, is only in the
ratio of 10 to 4, it is probable that in the slight difference of
angles that occur in this instance the resistances may be taken
as equal upon every part, without any material deviation from
truth. If this reasoning be correct it will reduce the question,
so far as utility is concerned, within a strictly abstract mathe¬
matical enquiry.

It has been found by experiment that the shape of the
hinder part of the spindle is of as much importance as that of
the front in diminishing resistance. This arises from the
partial vacuity created behind the obstructing body. If there
be no solid to fill up this space a deficiency of hydrostatic
pressure exists within it. and is transferred to the spindle.
This is seen distinctly near the rudder of a ship in full sail,
where the water is much below the level of the surrounding
sea. The cause here being more evident and uniform in its

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nature may probably be obviated with better success, inasmuch
as this portion of the spindle may not differ essentially from
the simple cone. I fear, however, that the whole of this
subject is of so dark a nature as to be more usefully investigated
by experiment than by reasoning, and in the absence of any
conclusive evidence from either, the only way that presents
itself is to copy nature ; accordingly I shall instance the
spindles of the trout and woodcock.

OF GREAT BRITAIN.

CONCLUDING REMARKS.

We regret to have to record the death of Mr. F. D.
Artingstall, of Manchester, a contributor of interesting results
in experimental aviation and a valued correspondent ever since
the formation of this Society.

It will be in the recollection of some of our earlier Mem¬
bers that Mr. Artingstall was the Author of a Paper read
before a General Meeting and published in the First Annual
Report, detailing some experiments conducted by himself.

A resume of these trials will be interesting at this time, as
the object which he was endeavouring to accomplish by the aid
of steam has lately been obtained by the torsion of India-rubber.

This variation in the experiment, admitting of more ready
manipulation within the bounds necessary for the accurate
adjustment and observation of wing-action as to angle, contour,
and material, may yet conduce to the accomplishment by steam
of the results which Mr. Artingstall only partially attained.

He says, speaking of locomotive engines, — “ Seeing the
vast amount of, power in those machines, with more zeal than
science I thought it would be no very difficult task to make an
engine to fly by steam. I soon contrived one, but under the
common impression that it only required power and lightness
to accomplish flying, which is but true to a certain extent.
Another popular error I had fixed in my mind, namely, that
for the up-stroke the wings must be valvular, to let the air
through.”

He then made a model engine, described in the First
Report.

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"When all was ready for a trial I suspended the machine
by a cord from the ceiling of a room to about oft. from the
floor, then got up steam, and allowed it to accumulate so that
there would be a good pressure to start with. When the steam
was turned on. the wings worked vigorously, but the machine
jerked up and down, whirled round, rushed from side to side,
and in fact performed all kinds of gymnastic movements within
its limits (except flying), to the great amusement of the par¬
ticular friends invited to witness the experiment."

Eventually the boiler exploded. Being repaired — "I said
to myself, if my engine will not absolutely fly. what amount
of gravity will be overcome by the action of its wings ? To
ascertain this I suspended the machine from the end of a long
balance or scale-beam, so that 1 could counterbalance it with
weights at the opposite end, but I found on trial that, the
up-stroke of the wings drove the engine down and the down-
stroke up. so that when at work it beat up and down violently.
This agitation of the balance prevented me from ascertaining,
with any degree of accuracy, even the effect of the down-stroke.
I therefore concluded that the engine should work four wings
instead of two : they would thus counteract each other and
keep up a continuous buoyancy, as one pair of wings would be
going up whilst the other would be descending : but this plan
I never carried into operation, for a second explosion ruined
my engine, but l now know that it would not have succeeded.

He then constructed a set of vanes, fixed at the top of an
upright shaft and driven horizontally by high pressure steam,
thinking that the whole might ascend, trying various shapes
and dimensions of vanes or screws, ultimately urging the engine
to great pressure until the joints were beginning to leak and
the connecting rods to bend : all to no effect, except to prove
that enormous power is not necessary for flight, as the whole
did not exceed the weight of a goose, and although there was

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exerted the power of a whole flock of geese its buoyancy was
below the weight of one. He then details two experiments
as follows : —

“ The first was this : I made an engine to work by com¬
pressed air, but, notwithstanding its great power compared
with its weight, no satisfactory results were obtained. I
considered that the wings were too short and broad ; I therefore
made a pair of long narrow ones, which made the thing look
somewhat like a swallow on a large ‘ scale. When this was set
in motion by a very moderate pressure, it felt as if it would
launch off from my hand into the air ; however it did not
do so, but when I let it go off it descended to the' floor
with a slow motion, something like a sheet of paper or a
wounded bird. I thought the reason of its not actually
flying was the want of more angular action or greater sweep
of wing, and more power, so I altered it accordingly. I
then tried it, but to my astonishment found that it would fly
little better than a tailor’s goose ; thus the greater power and
sweep had made it far worse. This I accounted for on the
principle that, in the first instance, the power and sweep
corresponded better to the size and speed of the aerial waves 01
pulses excited by that peculiar shaped wing. Not being able
again to obtain the same results, and finding that compressed
air was very irregular in its action and of short duration, to
test the principle further I made another engine to be moved
by steam. Its construction was as follows : — On the top of a
small but strong steam-generator I screwed a steam-tight
movable joint ; to this joint was secured a long brass pipe-
about three-eighths in internal diameter, and to the end of
this pipe I fixed my engine and wings only (i.e., not the boilei).
The brass tube gave no support to the engine, for it was jointed
to the top of the steam boiler as before stated, and in some
measure represented the string of a kite, only it conveyed steam

AERONAUTICAL society

to the engine. When all was ready the generator was put on
the fire of the smith’s forge. The engine and wings, at the
end of the long pipe, rested on a post or stump about 2ft. from
the ground. I turned the steam on at the generator, when, to
my great satisfaction, the engine instantly flew into the air, and
kept itself up to the length of its tether. I increased the power
of the steam until the wings began to emit a drumming sound,
when suddenly they both broke off close to the engine, which
of course came down like a stone. I now became weary of
these experiments, which produced me neither honour nor
profit, but quite the reverse.” * * * *

Mr. F. W. Brearey states that in the numerous experiments
which he has tried with wings for the purpose of illustrating
his Lecture he has made an effective model of what had
previously proved to be a failure, by simply reducing the arc of
vibration of the wing. Mr. Artingstall was very near to a
success at the time he abandoned that particular experiment.
Our French confreres have quoted him upon several occasions,
and perhaps these reminiscences will be interesting to them as
well as to us.

His last Letter to the Honorary Secretary is dated the
18th February. 1877. The following is an extract : —

“Notwithstanding I consider Aeronautics to be looking
well, yet a strange apathy has come over me on the subject.
The words of a clever but rather fast young friend of mine
come forcibly to my recollection, although he went to his long
home more than thirty years ago. One day he had been
assisting me at an aeronautical experiment, and seeing him the
following day I asked him ‘ What he thought ought to be the
next move ? ’ He replied. • If I were in your situation the next
move would be to stamp my foot upon the model, throw it to
the scrap metal, and wash my hands ot the whole business for

OF OREAT BRITAIN.

ever.' ‘Oh.’ I said, ‘just your prompt mode of despatching
business.’ ‘Well,’ said he. ‘I'm off to my dinner. You come
and dine with me and I will give you my reasons for this
advice.’ So we posted off.

•‘After dinner he began thus — ‘Now, Artingstall, I have
too much respect for you to allow you to make a fool of
yourself if I can prevent it. I acknowledge that you have
made a complete convert of me, and I believe that practical
flight will ultimately be accomplished ; and if you could make
an aerial machine that could practically fly, that would be a
good spec, and I should say astonish the natives with it as soon
as possible ; but experience has shown that such inventions as
a rule require years, nay ages, to perfect (the steam engine for
example), and that the pioneers of them lose their lifetime and
money without either honour or profit, but just the reverse.
Though they may make discoveries essential to subsequent
success, yet even these discoveries will not be appreciated until
success has crowned the undertaking, and perhaps the discoveries
themselves may be put in other language and form so as to be
“cabbaged” by some enterprising “scientific” man to glorify
himself.’ My reply to all this was ‘ If your theory had always
been acted upon we should have remained savages or barbarians.’
He acknowledged this, but said ‘ He would let those who had
a fancy for it do as they had a mind, but he was not ambitious
that either himself or friends should become pioneers to science
without any immediate benefit.’ I saw much truth in his
remarks, and soon after abandoned aeronautics until the
Aeronautical Society was formed.

“ Say if I can in any way assist you in your Lectures on
Aeronautics.

•• I have tried the French aerial toys. The power required
is enormous compared with the small weight raised and the
short duration of flight. Unless greatly improved, to speak of

100

AEBONAUTICAI. 800IBTY

them as models for practical flight is simply preposterous.
Well might M. P^naud fear that it will be many years before
aerial navigation will be realized. I expect before long to show
something better than aeroplanes and screws, or even wings
driven by the irregular power of rubber.”

It is melancholy to have to bear witness to the truth of the
foregoing remarks ; nevertheless we are certain that there are
workers amongst us who will not be deterred by them any
more than was Mr. Artingstall.

He further remarks in another place that “ there is
no cessation of buoyancy during the up-stroke of the wing,
but the body of the bird, while the wings are in action, is
as perfectly buoyed up as if it were the car of a balloon.”

In the models previously referred to, this perfect buoyancy
and direct horizontal flight are shown to perfection.

Until M. Penaud devised the simple mechanial means of
vibrating the wings we were unable to imitate the flight of
the bird. We can now, however, observe at our leisure the
action of different shapes and dimensions of wing surface.
We can satisfy ourselves that flight can be performed without
calling into action any valvular system of feathers. We shall
soon ascertain whether any opening out of the feathers in the
up-stroke can by any possibility be made effective in imitative
flight.

Mr. Artingstall in one of his Papers says that '• the wings
of all flying animals have a compound vibration, viz. — what is
commonly called the up-and-down stroke, and also the vibration
of the wing on its front edge, thereby causing the wing to
traverse a kind of wave track. This motion produces a powerful
pulsation of the air, perhaps like waves of sound, which gives
buoyancy to the bird, and is totally independent of waftage or
the common resistance of air. All flying animals,” he says,

OP GEE AT BRITAIN.

101

“ drive a current of air from the front edge of the wings to the
back, as may be proved by presenting the back edge of a bird’s
wing, when in motion, to the flame of a candle. This current
of air has a lateral pulsation which, by the proper use of the
wing, is converted into buoyancy.”

All this is demonstrable, and we may say that “ the way
of the eagle in the air” is no longer a mystery.

Considerable activity, in a quiet and unobtrusive fashion,
has been evinced among a few of our Members, and although
the results may not for some time to come appear before the
public, yet they are sure to produce good fruit. The unhappy
state of trade has of course had a very bad effect upon experi¬
mental research, for none of our working Members are
“millionaires.” We are glad, however, to be enabled to say
that there is not the least sign of “surrender” among these
industrious and indefatigable workers with brain and fingers.

In the opinion of some, the Society ought to be a partici¬
pator in the fund allotted for the endowment of scientific
research.

There are those amongst us who are capable of labouring
for the advance of science without hope of ultimate pecuniary
recompense.

The institution of the Aeronautical Club has been pro¬
ductive of some interesting intercourse amongst some of the
practical workers and those of the Members who are inclined
to show more than ordinary interest in their labours. The
Club is supplementary to the Society, but in its working quite
independent. It meets from October to May inclusive, the
third Tuesday in each month, and to these Evening Meetings
none are admitted except Members of the Aeronautical Society,
at an additional Subscription of 10s. 6d.

EF.

102

AERONAUTICAL 80CIETY

Mr. Fred. W. Brearey would feel great satisfaction in
handing over to the Widow of the late Mr. Artingstall any
Contributions which may be entrusted to him in response
to the following communication : —

“ Cheetwood, Manchester,
“July 16, 1877.

“Mr. Brearet,

“ Sib, — I have to announce to you the death of Mr. Frederick
Artingstall, of 248, Collyhurst Road, in this City, and to state that,
owing to a great extent to his scientific pursuits, he has left his Widow
and a helpless Daughter (subject to fits) totally unprovided for.

“If the Noblemen and Gentlemen with whom you are associated
in the' Aeronautical Society could kindly contribute a small 3um to
relieve her present and very pressing necessities, you would be con¬
ferring a kindly and truly-charitable deed.

“I have been acquainted with the late Mr. Artingstall for the
last 35 years, and can bear testimony to his peaceful and conscientious
character during the whole of this period.

“I am, Sir,

“ Yours very respectfully,

“Fred. W. Brearet, Esq.,
“ BlacJckeath.

“ELIAS NATHAN.

“Mrs. Artingstall’s address is 248, Collyhurst Road, Manchester.”

OF GREAT BRITAIN.

103

J. H. STOREY,

EIT GI3STEER <S& MODEL MAKER,

37, FARRINGDON STREET, E.C.,

Having been engaged for upwards of four years in making
the apparatus for Mr. Moy’s experiments, can bring to bear
a large experience in constructing Models for experiments

in Aeronautics.

Reference by kind permission to Fred. W. Brearey, Esq., Honorary
Secretary to the Aeronautical Society, Maidenstone Hill,
JBlackheath, s.E.

104

AERONAUTICAL SOCIETY

MEMBERS.

Alexander, A., M.A., C.E., Cyclops Steel and Iron Works, Sheffield;
of the Council

Anderson, Capt. A. Dunlop, 23rd Punjab Pioneers, 21, Lennox Street,
Edinburgh

Arbuthnot, H. Gough, 40, Prince’s Gate, s.w.

Argyll, the Duke of, F.R.S. ; President of the Council

Armour, J ames, C.E., Gateshead

Ashbury, James, M.P., 66, Grosvenor Square, w.

Ballard, Stephen, C.E., Colwall, Great Malvern
Barber, William, 9, “The Boltons,” Kensington, w.

Baring, Colonel, 36, Wilton Place, s.w.

Barnett, E. W., 25, Lancaster Gate, w.

Barrett, Frederick, Langley House, Grove Lane, Camberwell, s.E.
Baxter, Richard, F.R.G.S., 19, Leinster Gardens, w.

Beadon, Captain R.N., Creechbarrow, Taunton
Bell, Charles W., Roche Court, near Salisbury
Bennett, T. J., 20, Little Clarendon Street, Oxford
Biddle, Dr., Kingston-on-Thames
Blass, E., C.E., Cleve, Prussia
Borthwiok, Lord, 35, Hertford Street, May Fair
Bourne, John Fred., C.E., Louth, and Civil Service Club
Bourne, Mrs., Hilderstone Hall, Stone, Staffordshire (Associate )
Brearey, Fred. W., Maidenstone Hill, Blackheath ; of the Council, and
Honorary Secretary

Bright, Sir Charles Tiltston,F.R.A.S., 26, Duke Street, Westminster,
s.w. ; of the Council

Brooke, Charles, M.A., F.R.S., 16, Fitzroy Square ; of the Council
Brooks, Maurice, M.P., 10, York Terrace, Regent’s Park
Brown, Davxd Stephens, The Norton, Tenby, Pembrokeshire

OF GREAT BRITAIN

105

Browning, John, F.R.A.S., 63, Strand; of the Cowncil
Brownjohn, William Wade, Jun., United Service Club
Brunton, N. W., 116, Belsize Park Gardens, N.w.

Burnaby, Captain, Royal Horse Guards ; of the Cowncil
Burrell, Edward, The Hermitage, 7, Melina Place, St. John’s Wood
Burton, Rev. Roger Taylor, M.A., The Vicarage, Great Tey, Kelvedon,
Essex

Chaplin, James C., 12, Craven 'Hill, Hyde Park
Chatto, Andrew, 74, Piccadilly.

Clare, Walter F., Engineer, 2, Agnes Cottages, Elm Grove,
Hammersmith.

Crestadoro, Dr., Free Libraries, Manchester

Crosland, J. M., Holly Lodge, Thistle Grove, South Kensington

Davies, Charles, 47, Pall Mall

Dawson, G. J. Crosbie, C.E., The Cliff, Preston, Lancashire.

Deck, Arthur, King’s Parade, Cambridge

Decruz, E., Seetarampore Collieries, Raneegunge, Lower Bengal, India
Delane, John T., 16, Serjeants’ Inn, Fleet Street
Dk Satrustequi, Don Joaquin Marcos, Consul General de Espaiia,
21, Billiter Street

De Villeneuve, Dr., Rue Lafayette 90, Paris

Dufferin, Earl of, 8, Grosvenor Square ; Vice-President of the Council
Ellis, James, 337, Strand, w.c.

Elphinstone, Lord, 24, Carlton House Terrace
Emden, Walter, 76, Russell Square

Frost, Edward P., J.P., West Wratling Hall, Linton, Cambridgeshire
Glaisher, James, F.R.S., F.R.A.S., fee., Blackheath ; of the Council
Gordon, R. Newton, 1, Blomfield Road, w.

Greenway, Henry, M.R.C.S., Plymouth
Greetham, Thomas, 26, Bedford Row, w.c.

Grosvenor, Lord Richard, M.P., F.R.G.S., 76, Brook Street, w. ;
Vice-President of the Council

Hall, Alexander Lyons, F.R.G.S., 49, Blenheim Crescent, Notting Hill
Hall, George Samuel, Saville House, Billingshurst, Sussex
Harper, J. E., 257, Southampton Street, Camberwell
Harrison, A. Stewart, 133, Upper Thames Street

106

AERONAUTICAL SOCIETY

Hat, Rear-Admiral Lord John, 149, Piccadilly ; of the Council
Holland, Robebt, Stanmore, Middlesex
Hudson, C. Donaldson, 51, South Audley Street
Jay, R. C., 54, Alexandra Road, Cambridge Gardens, Kilbum, w.
Jennings, William, F.R.G.S., 13, Victoria Street
Knight, John, Oakhill, Hildenboro, Kent
Krueger, W. G., Downeville, Sierra County, California
Latham, Baldwin, C.E., 7, Westminster Chambers
Le Feuvbe, Wm. H., C. E., F. R. G.S., St. Antholin’s Chambers,
26, Budge Row, Cannon Street, e.c. ; of the Council
Lilienthall, Otto, Albrecht St. 13, Berlin
Lindsay, Lord, 47, Brook Street, w.

Londondebby, the Marquis of, Londonderry House, Park Lane
Ludeke, J. Ebnest F., 15, Wilmot Place, w.

Macdonald, Colonel, 27, Park Lane, w.

Manners, Lord John T., Guards’ Club, s.w.

Marriott, Frederick, San Francisco, California
Matthews, Edwin, 26, Bedford Row, w.c.

Maxwell, Captain R. J., Army and Navy Club, s.w.

Mobrieson, Colonel R., Oriental Club

Mot, Thomas, 37, Farringdon Street

Nees, Christopher, Telegraph Director, Elsinore, Denmark

Newman, Frederick, C.E., 51, Belsize Road

Ofenheim, Victor R. Von, Schwarzenberg Strasse 18, Vienna

Ohren, Magnus, A.I.C.E., F.C.S., Lower Sydenham ; of the Council

Osleb, Abraham Follett, F.R.S., Birmingham

Owen, Captain, R.A., 43, The Common, Woolwich

Penaud, Alphonse, 14, Rue Castellane, Paris

Perigal, Henry, Jun., 9, North Crescent, Bedford Square

Phillips, H. F., Crown Villas, Upper Norwood

Phillips, W. H., Cemetery Road, Nunhead

Risley, J. B., C.E., Brondeg, Ferryside, South Wales

Roberts, Major H. C., 48, Hereford Road, Bayswater

Senegal, P., 261, Brompton Road, s.w.

Siemens, C. W., C.E., F.R.S., 12, Queen Anne’s Gate, Westminster
Stringeellow, John, Chard, Somerset

OF OBEAT BRITAIN.

107

Sutherland, the Duke of ; Vice-President of the Council
Thorman, A. J., 281, New Cross Road, s.E.

Tolme, J. H., C.E., 9, Victoria Street, Westminster

Tracey, The Honourable Henry Hanbcby, Gregynog Newton, Mont¬
gomeryshire

Walker, Charles Clement, Lilleshall Old Hall, Salop
Walker, Thomas, 24, Oxford Street, Birmingham
Wenham, F. H., C.E., V.P.R.M.S., Padnall Hall, Chadwell, Essex ; of
the Council

Wilson, George, 7, Church Terrace, Union Grove, Clapham
Wright, Henry, Stafford House, St. James’ ; of tike Council
Yorke, Pierce Wynne, Dyffryn Aled, Abergele

108

AERONAUTICAL SOCIETY

The following SPECIFICATIONS OF PATENTS

Are Presented to the Society by the Commissioners.

Date. No.
1876.

Jan. 27. 327.

Feb. 3. 439.

Subject.

Patentee.

Improvements in transmitting \

motion on, or in, water, the air, ( r t> i,
or on land, and in the means or (
apparatus employed therefore ;

A new Machine to travel along a'
line attached to a kite, or any
high point, and carrying up
and dropping any material f
placed thereon, the machine |
returning to the hand . J

J. J. Snow.

June 8. 2393. A new improved method of direct- ) ,, -r, , „

ing and controlling Balloons... j un e .

July 11. 2827. Improvements in producing motive'!

power, in the application of
such improvements to useful \ E. H. C. Monkton.
purposes, and in the Apparatus |
necessary for effecting the same J

July 28. A new or improved Flying or Aerial Toy — Communi¬

cated by La Soci£t£ Dandrieux Gravier et Cie.

BOOKS. PAMPHLETS. &c., RECEIVED.

Lex Nowveaux Ballons, par Arsbne Olivier — several copies — By the
Author.

Navigation Aerienne, par M. P. Coi’denons, Professeur de Matematigues,
de Lyc.ee de Rovigo — By the Author.

Smithsonian Report for 1874 — By the Board of Regents, Washington.
The Monthly Numbers of L' Aeronaut*. — By M. de Villeneuvk.

Cfotlftjj Annual depart

OF THK

AERONAUTICAL SOCIETY

GREAT BRITAIN.

FOR THE YEAR 1877.

PRINTED CT

HENRY S. RICHARDSON,

GREENWICH.

Reproduced and printed photolilho offset Jor
Peter Murray Hili. (Publishers) Ltd.

73 Sloane Avenue
London S.W.3
] 956

Hu permission of the Royal Aeronautical Society

MADE AND PRINTED IN GREAT BRITAIN BY
D. R. HILLMAN & SONS LTD., FROME

THE

AERONAUTICAL SOCIETY OF GREAT BRITAIN,

Pregftimt,

HIS GRACE THE DUKE OF ARGYLL, K.T.

Ftce=Pte8foent0,

HIS GRACE THE DUKE OF SUTHERLAND.
RIGHT HON. THE EARL OF DUFFERIN.

LORD RICHARD GROSVENOR, M.P.

^onotarg Secretary

FRED. W. BREAREY, Esq.

f^crnotatg Solicitors,

Messrs. MATTHEWS & GREETHAM, 26, Bedford Row.

Council,

A. ALEXANDER, Esq., C.E., M.A, Sheffield.

FRED. W. BREAREY, Esq., MaidenBtone Hill, Blackheath.

Sir CHAS. T. BRIGHT, F.R.A.S., 26, Duke Street, Westminster.
CHARLES BROOKE, Esq., M.A., F.R.S., 16, Fitzroy Square.
JOHN BROWNING, Esq., F.R.A.S., F.R.M.S., 63, Strand.
Captain BURNABY, Royal Horse Guards.

JAMES GLAISHER, Esq., F.R.S., F.R.AS., Blackheath.
Rear-Admiral Lord JOHN HAY, C.B., 149, Piccadilly.

W. H. LE FEUYRE, Esq., C.E., F.R.G.S., 28, Brunswick Gardens, w.
Lord LINDSAY, F.R.AS., 47, Brook Street.

MAGNUS OHREN, Esq., A.I.C.E., F.R.S., Lower Sydenham.

F. H. WENHAM, Esq., C.E., V.P.R.M.S., Padnall Hall, Chadwell,
Essex.

HENRY WRIGHT, Esq., Stafford House, St. James’.

with power to add to their number.

Member’s Subscription jCI. Is. per annum, dating from the day of Election.
Ladies may become Associates upon the same terms.

Ctotlffjj Annual Import

OF THE

AERONAUTICAL SOCIETY OF GREAT BRITAIN,

FOR THE YEAR 1877,

Containing an Account of the Proceedings and a Selection from the
Papers and Communications received by the Society during the
year, with Concluding Remarks upon the present state of the
Science.

The Annual Meeting of Members of this Society was
held in the Room of the Society of Arts, Adelphi, by the
usual kind permission of the Council, on the Evening of the
18th of June; Mr. James Qlaisher, F.R.S., in the Chair.

The Minutes of the preceding Meeting were taken as

read.

The Chairman : Ladies and Gentlemen, — I am sorry to
say that the Duke of Argyll has informed our Secretary that
he has been engaged for this night for two months, or he
would have been here. I wish he had been present, for it is
now some time since he occupied this Chair. It is two years
since I occupied it. At that time I spoke enthusiastically of
Mr. Moy’s Aerial Machine. I was in hopes that as on one
occasion it raised 1201bs., we might by this time have
advanced to a multiple of that weight. I met Mr. Moy some
time ago, and he said he had been so much engaged that he
had not had time to proceed with his invention, but he had
not given up the idea. He said that the only thing that had

AERONAUTICAL SOCIETY

prevented him carrying on an investigation of so much interest
were matters that absolutely required his attention. His
feeling and his heart, he said, were in the cause. It was only
this morning that Mr. Brearey saw me and told me that he
would probably require me to take the Chair. I have now to
call upon Mr. Jay to exhibit a model of the figure 8 movement
as a propeller for aerial use.

Mr. Jay exhibited a Model of his invention, and read the
following Paper on

THE FIGUBE 8 MODEL AS AVAILABLE FOB
AEBIAL USE.

In placing this Model before you I venture to suggest
that the attention of the Members of this Society should
especially be directed to finding or inventing a propeller which
will enable us to grasp the air in such a manner as to utilise
the power we possess in the steam-engine. We are at present
unacquainted with any aerial propeller which does- not require
an enormous expenditure of power ; and when I regard the
ease with which many birds raise themselves from the ground,
I cannot but think there is much room and opportunity foi
improvement in our mechanical appliances, and that the
difficulty may be overcome.

The model I produce illustrates what I believe to be the best
(that is to say, the figure erf 8 or sculling) action, but the same
movement may no doubt be obtained by a more simple mechanical
arrangement. Either a direct lifting, or a lifting and pro¬
pelling action, may be produced by this arrangement. The
motion is obtained by means of two cranked axles revolving in
opposite directions, and connected together by rods on which
a slide works. The roots of the wings are connected to the

OF GREAT BRITAIN.

slide by means of universal joints, and the fulcra are also
supported on similar joints to ensure freedom of action. The
slide is attached by a rod to a crank having a greater throw
than the cranks previously referred to, so that the wings may
traverse a greater horizontal than vertical space. By this
action the fore-edge of the wing is depressed at the commence¬
ment of the backward stroke and elevated at the commence¬
ment of the forward stroke, thereby avoiding the back pressure
which would occur in any other reciprocating motion.

The Chairman (referring to the model which had only
one pair of wings) : There would be more wings than one ?

Mr. Jay : There might be wings beyond those.

The Chairman : Was not that part of your proposition?

Mr. Jay : Oh yes. I have thought for some time past of
placing wings behind each other, so that each wing would take
a fresh volume of air.

The Chairman : Has not Mr. Moy adopted something of
that figure to his machine ?

Mr. Moy : No, not exactly that.

At the request of Mr. Brearey the model was passed round
and examined by the Meeting.

Mr. Moy (to Mr. Jay) : Can you increase the angle ?

. The Chairman : Do you think the inclination is enough?

Mr. Jay : There might be a little inclination to make the
wing fly higher up. The object is to raise the back edge of
the wing and enable the back strokes to catch the air and
spring it up. I have another arrangement of a similar sort on
a smaller scale, that will raise itself with a spring two or three
strokes off the ground.

The Chairman : Has any gentleman any remarks to make
upon the model? if not I will ask you to return thanks to
Mr. Jay. Thosb in favour will signify the same by holding up
their hands.

AERONAUTICAL SOCIETY

A vote of thanks was given accordingly.

Mr. F. W. Brearey, Secretary of the Society, exhibited
various models, much to the interest and satisfaction of the
audience, and read the following paper on

THE PROBLEM OF FLIGHT.

It has been suggested to me that I should exhibit
to the Members of this Society the models with which I
illustrated my late Lecture upon the “Problem of Flight,”
delivered at the London Institution. It will be conceived
how the subject was handled, and how it led to the
consideration of the possibility of its imitation by man. In
other words it was a Lecture upon Aerial Navigation, and I
almost think it was the first public Lecture upon such a
subject delivered before a London audience.

I had previously announced that I was prepared to deliver
a Lecture upon “Aerial Navigation,” but it was significantly
suggested that the title had better be the “ Problem of Flight.”
So under that title I addressed a crowded audience, whose
wrapt attention was somewhat remarkable.

The profound ignorance which has prevailed, not only
amidst the mass, but amongst men of eminence in other
scientific studies, as to the principles upon which the students
of our special branch of science depend for the ultimate
accomplishment of Aerial Navigation, induced me to turn
Lecturer.

The literature upon this subject has been greatly multiplied
since the formation of this Society in 1865. The first Report
was issued in 1867. In 1868 the French Aeronautical Society
published their first Report, which took the form of a monthly
bulletin. Our Aeronautical Exhibition in that year at the
Crystal Palace was the occasion which led to its issue. The

OP GREAT BRITAIN.

first numbers were chiefly devoted to notices connected with
that Exhibition to which their Society sent a Commissioner in
the person of their talented Hon. Secretary, M. de Villeneuve.
The Report has been issued monthly ever since. Their Mem¬
bers seem to take more personal interest in the subjects brought
forward than do ours. It may perhaps be only conjecture.
Certain it is that their invention seems more stimulated, and
has taken the form of some very effective models with which
they illustrate flight.

These were all that I required in demonstration of what I
had to advance in my Lecture.

I have heard it said by one of the Members of our Society
that we shall never learn anything from models. This from a
gentleman who is always going to construct a large apparatus,
but has not yet commenced it. I, however, emphatically deny
the proposition.

Taking these French models as my foundation I have
constructed, re-constructed, and improved upon them. My
mind has been stored with significant but delicate facts which
would altogether have escaped my notice but for the action of
the models ; and the papers which have been read before the
Society in this room have been invested with a new interest.

Gentlemen, by your encouragement I have been enabled
to act as Honorary Secretary of this Society, and I am thereby
placed in a position to extend that encouragement to corres¬
pondents and workers in many parts of the world, and I grudge
no time spent in contributing to the elucidation of the mystery
which man has made of flight. No other subject, except that
of daily bread, engrosses my thoughts, and the remainder of
my life (accidents alone excepted) will be as the last 12 years.

It is not my intention to deliver a Lecture upon Aerial
Navigation to the Members of this Society.

Much of the information which I can give with great

AERONAUTICAL SOCIETY

advantages to others, has been within the reach of the Members
in the published Reports, and in other publications of which
they are no doubt cognizant.

I will therefore commence to show you how I treat the
subject in my Lecture ; and first I illustrate flight by projection
by these familiar paper models.

Models projected by the hand.

I then proceed to flight by gravity alone, showing how
the bat, hanging by its claws, by simply releasing itself attains
its first flight.

Liberation of BA TS from the top of the room.

Then I show how the application of force neutralizes the
force of gravity. In this model the screw propels a plane
surface, which here is represented by wings. It is made after
the model of M. Penaud, of the French Society, improved as to
the screw by myself.

Flight by force and surface.

It is obvious that different forms of surface may be
employed here with instructive results for future work. For
instance, I have, in this next model, adapted the albatross
form of wing, this model being about half the length, viz., 7ft.,
but the breadth being only one-fourth or two inches, that of
the albatross being about 8in.

Flight of albatross model.

This class of experiment may be greatly varied with a
view to ascertain the weight which can be carried under a given
surface. I think it will be found that the angle of inclination
with which the wing advances will have to be increased with
the weight, and also the force in the same relative proportion.

I come now to demonstrate the propelling and supporting
surface in one, as in the wings of a bird, but first I show the
action of a wing as a propeller.

It is asserted by some naturalists, in explanation of this

OV GREAT BRITAIN;

effective wing action, that the feathers of a bird s wing are
made to underlap each other, so that in the downward stroke
the pressure of the air closes them upwards against each other
and converts the whole series into one connected membrane,
through which there is no escape ; whilst in the upward stroke
the same pressure has precisely the reverse effect. “ It opens
the feathers,” says the Duke of Argyll, “separates them from
each other, and converts each pair of feathers into a self-acting
valve through which the air rushes at every point.” The Duke,
in his “Reign of Law,” so thoroughly recognizes, in another
place, the immense importance of the concave and convex sur¬
faces in gripping the air in the one case and evading it in the
other, that I can scarcely think of him as laying much stress
upon the valvular system of feathers. Dr. Pettignew, whose
researches give weight to his statement, estimates this difference
as two to one.

I may perhaps undervalue this valvular theory, and it is
possible that, in the case of some birds which appear to have
flat wings, the theory may be in part correct, but it is quite
certain that in the wing propeller I shall now show you, the
convex and concave arrangement is most effective, leaving
nothing to be desired.

Wing Experiment.

' [Here the Lecturer stood upon a pivoted stool, and holding
the artificial wing perfectly level, waved it up and down, by
which action he was revolved.]

I will now proceed to the practical application of the
concave-convex theory by exhibiting a model after the con¬
struction of M. Penaud, of the French Society. The Freneh,
as a flighty nation, are fairly entitled to this invention.

I have been experimenting with various forms of wings,
and have been enabled to achieve the leisurely flight of the
crow and the swift flight of the swallow.

AEBON AUTIC AL SOCIETY

I hope that, after this, we shall hear less about Archytas
and his wooden pigeon.

Flapping birds of various kinds .

My Lecture concludes with observations upon the vertical
screw, and here again I resort to M, Penaud’s Helicoptere in
illustration. Some very pretty toys are sold somewhat similar
in principle.

I have now gone over the principal topics contained in the
Lecture, but I cannot conclude my Paper without some allusion
to a subject which has given opportunity for much private com¬
ment and some public correspondence, and about which, when
lecturing at various places in the Country, my opinion was
solicited — I mean the use of Balloons in Polar Exploration.

I shall guard myself against any extreme opinion now,
as I did upon those occasions in which I was appealed to. I
enter upon the subject with a view to elicit a discussion, as I
think that it is a legitimate one for this Society to entertain.

The Balloon has a sphere of its own quite independent of
its shape, unapproachable by any other invention, and the
question for discussion is — “ TTns the late Polar Expedition
such an opportunity as afforded any reasonable chance for the
useful employment of the Balloon?"

The first remark that I feel called upon to make is, that
unless a Balloon, with the necessary means for its inflation,
form part of the vessel’s equipment, the world will never learn
practically how far its use may be made subservient to Polar
Research.

Do there exist any obstacles to the inflation of a Balloon
in the Polar Regions with hydrogen gas ? Would the moisture
evolved in the manufacture of gas convert the envelope of the
Balloon into a mass of ice ? which I apprehend would be fatal,
if irremediable.

I hope to learn that the gas could be caused to enter into
the Balloon in a dry condition.

OF GREAT BRITAIN.

There is still another difficulty that occurs to me, which
is that the sulphuric acid would consist of blocks of ice.

I merely mention these as difficulties to be overcome, not
forgetting that coal has been discovered in these regions.

All the materials and apparatus being conveyed to the
place of destination, there should be no difficulty in the
inflation. Giffard’s Balloon, exhibited in 1869 at Cremome,
was inflated with pure hydrogen, and could carry upwards of
16 tons.

The Balloon successfully inflated, then what would be the
work expected from it ?

When I read the Report of that 70 days’ journey, to
accomplish I believe about 70 miles^ at a fearful cost of life
and suffering, consequent upon having to drag over ice hum¬
mocks, sledges containing provisions, I exclaimed to my friends
“why the whole of the stores could have been conveyed over
their heads, and the men holding the ropes of this floating
observatory would have been assisted by the upward tendency
of the balloon.” Would the daily consumption of stores com¬
pensate the leakage of gas ? Major Beaumont, in his history
of the Balloon as employed in the American War, says “that
the Balloon when inflated can, unless in very windy weather,
be very readily carried. Twenty-five or thirty men lay hold
of cords attached to the ring and march along, allowing the
machine to rise only sufficiently to clear any obstacle. He had
frequently,” he says, “seen it carried thus without the least
difficulty.” He further says “that there was always a small
amount of leakage, but, from the superiority of the varnish, at
the end of a fortnight, sufficient gas remained in the balloon to
enable an ascent to be made without its being replenished.”
The ascensive power of a Balloon thus conveyed for purposes
of war must be available at any moment for the two observers,
and the additional weight of the two guy ropes which it also

AERONAUTICAL SOCIETY

has to sustain, so that the necessity for the twenty-fire or
thirty men is explained ; but for the purposes of exploration and
the carrying of stores a very few pounds of ascensional force
need be requisite. These stores, however, upon being removed
from the Balloon ; or the sledges, which might be partly buoyed
by the Balloon, being detached, then, could not the Balloon
be utilized to survey the Country from some thousand feet or
more by means of a let-out cord ?

I hope that I am addressing some Arctic Navigators who
have been invited here this evening, and who will be able to
tell us if any insuperable difficulties exist to prevent the
employment of the Balloon as suggested, and also whether
upon the organization of the late expedition the subject was
considered, and if so, and abandoned, then upon what grounds.

I can conceive how in the hands of a naan great in
resources, a Balloon, under favourable conditions, oould be made
a valuable auxiliary, but I cannot conceive how (because there
might be a chance that those conditions may not turn out to
be favourable) such an adjunct should altogether be left out of
calculation.

I can imagine, for instance, the case of a carpenter called
into the next street to effect repairs, taking only such tools as
he might guess to be necessary, because an omission could be
readily remedied, but I cannot imagine him called fifty miles
from home without taking his whole basket-full.

Therefore I repeat my proposition — “ Was the late Polar
Expedition such an opportunity as afforded any reasonable chance
for the useful employment of the Balloon ? ”

The remarks of the author and the exhibition of models
were much applauded.

The Chairman : I am sure we must be all much indebted
to Mr. Brearey for the beautiful models he has produced, and

OF GREAT BRITAIN.

which are worthy of a great deal of attention. Perhaps there
are some Arctic voyagers here, or some one in the room
who can give an answer to Mr. Brearey’s proposition. The
question Mr. Brearey puts is, “Was the late Polar Expedition
such an occasion as to afford a reasonable opportunity for the
employment of Balloons?”

Mr. Reeoe : A surgeon of Plymouth, of the name of
Greenway, published in a paper a statement that several
months before the Expedition started he did communicate
with Captain Sir George Nares, and used the great name of
Mr. Coxwell in reference to a suggestion that the use of the
balloon would afford a greater extent of vision over the
country to be explored than could be obtained in any other
way.

The Chairman : Sir George Nares, at the time the
Expedition was planned, was in command of “The Challenger,”
and could hardly have received these suggestions.

Mr. Reece : The writer says he submitted them to
Sir George Nares and to the Admiralty, but the suggestions
were declined. With regard to hydrogen gas there would be
no fear of its efficacy. After it was generated it would pass
through ice, or would be so cold that it would maintain the
same temperature throughout the journey. Hydrogen gas
would be generated at a heat of 180°. It would then pass
through a tube and be chilled, and would remain at a
temperature of about 32°, so that there would be no fear of
its depositing a mass of snow or ice. That objection therefore
need not be entertained. There is a proposal made by
Mansfield in his work on ballooning, that the weight of a man
might be taken off by ballooning. A balloon of 18ft. diameter
would take off the weight of a man ; anu in this way a man
named Ward was able to leap in the forest, from tree to tree,
with a velocity of 15 miles an hour. In that case a man

AfiBONAUTICAL society

might guide a sledge of dogs at a great pace, and could convey
stores by this means to any point.

Mr. Moy : Perhaps Mr. Reece can tell us whether he has
had any practical experience of the nature of hydrogen gas in
a severe frost.

Mr. Reece : I have made experiments. I have submitted
the gas to intense cold, and it appeared to have no effect upon
it. I could hardly have expected that it would have any
effect. Faraday exposed it to cold 100° below zero and a
pressure of 800 atmospheres, and never found that either had
the slightest effect upon it. Neither had the most intense
cold or pressure that he could produce at the Royal Institution.

Mr. Simmons (the Aeronaut) read the following notes
bearing on the subject of the Paper : —

The hot-air balloon seems to be the best adapted to the
especial object —

lstly. Because in the presence of intense cold wind does
not exist, wind being the chief drawback to the inflation of
hot-air balloons in England.

2ndly. Because the more intense the cold of the air
surrounding the balloon, the greater the ascending power.

3rdly. The hot-air balloon during inflation will give off
sufficient heat from its surface to keep the men warm whilst
they are holding the net, and when the balloon is afloat no
inconvenience can be experienced from cold.

4thly. The time required for the inflation of the hot-air
balloon is about half-an-hour, and the preparation of the
apparatus for the inflation will never be found so troublesome
or occupy so much time as that for the hydrogen balloon.

5thly. The danger and annoyances from carrying oil of
vitriol will be obviated.

6thly. Hot-air balloons have no preparation spread upon
their surfaces that can sustain any injury, decomposition, or

OF GEEAT BRITAIN.

spontaneous combustion from being closely packed for a
lengthened period.

The entire weight of the balloon apparatus used at the
Royal Arsenal, Woolwich, was 12001bs., its diameter was 70ft.,
and the heat when inflated, taken 10ft. above the open neck
of the balloon, was 120° Fahrenheit.

The greatest difficulty against the inflation of a balloon
with pure hydrogen gas in intensely cold 'regions would be —
the keeping of the water in the retort from freezing whilst
charging or after being charged with water, until the vitriol is
poured in. The process of making pure hydrogen gas by
means of furnaces would necessitate the employment of
exceedingly cumbersome apparatus.

I should have been pleased to hear the experience of
those who had visited the Arctic Regions as to the probable
existence of wind during the times when the exploi'ations
would be carried on. When I alluded to the non-existence of
wind with intense cold. I confined mj^self to my own experience
in Canada.

Mr. Reece : As that gentleman has alluded to the
subject of the formation of hydrogen gas. I may say that no
one intended to form hydrogen gas by the use of a furnace or
by passing over iron filings. It would be produced by pouring
one part of sulphuric acid over four parts of water.

Mr. Moy : That freezes.

Mr. Simmons : No, that does not freeze. I am going to
ascend at Hyderabad in India by the use of that process.

Mr. Reece : According to the book published by Sir
George Nares, the average temperature during the Expedition
in the Arctic Regions was 30° Fahrenheit. That would not
have the slightest effect on a composition one part sulphuric
acid and four water. When you pour that on zinc the
temperature would rise to 180° If any one tries that in a

AERONAUTICAL SOCIETY

glass vessel lie could not keep his hand on it, so that any fear
of not generating the gas must be entirely visionary. We
must recollect that air expands only one 480th part.

The Chairman : One 491th by the most recent experi¬
ments, but one 500th part is near enough.

Mr. Reece : It expands one 480th part, so that you
would require great heat for an air balloon. A fire balloon
has enormous power, but nothing like one filled with hydrogen
gas.

Mr. Moy : The heat would be about 600°.

Mr. Simmons : The heat generated in a hot-air balloon
would be 120°. The weight of a balloon and all its para¬
phernalia might be 12001bs., the diameter 70ft., and it would
carry me into the air if the average heat were 120°.

Mr. Reece : With hot air there would be a danger of
setting the balloon on fire if it were composed of varnished
silk.

Mr. Simmons : They never are composed of varnished
silk ; they are unvarnished.

The Chairman : If no Gentleman has any more remarks
to make, before asking you to thank Mr. Brearey I would
observe that I am not aware myself that the subject of the
use of the balloon in the late Arctic Expedition was brought
under the notice of the Admiralty, and I do not know that it
was taken into consideration at all. I know they were much
pressed for space on board the vessels. Everything was
excluded that was possible to be excluded on account of the
want of room. No communication was made to me. Previous
to the undertaking of the expedition, Mr. Francis Galton had
written to me in reference to the use that might be made from
the whalers, which often proceed very far North, and I advised
the use of hydrogen gas balloons. I did not recommend the
use of the fire-balloon from the simple fact of the large size

OF SEBAT BRITAIN.

the balloon would have to be. If a balloon, of 70ft, diameter
had to be taken out, a very large space would be required.
Again, it could only be used in Summer time, wheat there is
wind in the Arctic regions. We know that in Russia and
Sweden in Winter time, when the temperature approaches zero,
it is nearly always calm. To realize the intensity of the cold
one must move the hand against the cold air -or run against the
air. No person standing in an atmosphere 70° below zero
would feel that the cold was so intense. It might be far more
painful when the temperature was above zero if the air were in
motion ; but the Winter is not the time when these experi¬
ments would be made : they would take place in the Summer,
when the temperature would be 40°, and i» the sun very much
hotter. I see no reason, however, why the balloon should not
be made available in various ways in Arctic Exploration, and I
do hope that if there is another expedition the balloon will be
tried and the question settled. It would certainly, if used in
connection with a sledge, enable the distance that could be
traversed in the day to be increased. With regard to the view
that can be obtained from the balloon : when I was half-a-mile
over London I could see Margate and Brighton and on to the
Norfolk coast. This shows you how much may be seen from
a comparatively small elevation. From the height of a mile
you can see nearly ninety miles, and even when a few hundred
feet high one is in a position to see over the country for several
miles ahead. In any case I hope that in the next expedition,
from whatever country it may proceed, not only one balloon
but several balloons may be taken out. I need now only
express the pleasure we all feel in' seeing these models.
Mr. Brearey has been working at them for a long time.* 'The
beautiful action — the bird-like action — of these models becomes
very interesting when we consider that it is produced by
mechanism, and I believe that by following up these experi-

aeronautical society

ments, even if the problem of flight be not solved, our knowledge
upon many points will nevertheless be greatly increased. With
these remarks I will ask you to give the warmest thanks you
can to Mr. Brearey, because it is to his energy and zeal, ever
since this Society was established, that we owe its existence
now. He frequently calls upon me, and is always occupied
with the investigation of some original and undecided point in
our subject. It is to him that I owe the honour and pleasure
of being here this evening. He came to me this morning and
would not take “No.” It is a great thing when a man will
not take “ No.” I gather from your cheers that I need not put
the vote. You have already thanked him by acclamation even
better than by vote ; and that you give him your warmest
thanks is proved by your cheers.

Mr. Brearey : I am very much obliged to you for the
kind terms in which you have spoken of me. It is the first
time in twelve years that I have received a vote of thanks, and
I appreciate it the more.

The Chairman : You see heartfelt quiet thanks are not so
much appreciated as noisy cheers. The question Mr. Brearey
wishes to have put is — “ Was the late Polar Expedition such
an occasion as afforded a reasonable chance for the employment
of the Balloon? ” I do not think Mr. Brearey wishes us to find
fault with the equipment of the expedition, so that it is
unnecessary to put the question as a motion. I will ask
Mr. Moy to read his Paper.

Mr. Moy then read the following Paper on

THE CHOICE OF MEANS FOE EXPERIMENTING IN

AERONAUTICS.

It is sufficiently apparent that very many minds are
occasionally exercised upon the Problem of Aerial Navigation,

OF GREAT BRITAIN.

and many persons rush into public notice with most crude
notions and the barest smattering of mechanical knowledge,
and fancy that this problem, coupled with their superficial
knowledge, will carry them on to fame and fortune at one
bound. It is the constantly unpleasant duty of our worthy
Secretary to answer courteously the very numerous applications
and proposals that are made to him. One very noisy individual is
now happily silenced — at least we hope so — whose plan was so
utterly absurd that it only required to be seen to excite ridicule,
being to all intents and purposes a hip-bath and a copying-
press, with which he was going to “ shake the scientific world
to its very foundations.”

One of the “modern antiques” lately brought very
prominently before the public is over 50 years old, and as it
has been frequently urged upon our Society, and I am afraid
will continue to be so, I wish to say a few words about it.

About the year 1825 it was proposed to surround a bal¬
loon with a horizontal sail, capable of being altered by the
aeronauts to any angle they pleased, and it was proposed, by
the alternate ascent and descent of the balloon, to compel it to
travel in any required direction by the dynamic result of the
pressure upon the surface of the sail.

This absurd idea has occurred to so many people, and has
be6n brought forward so often, that it is simply a perfect
nuisance to have to refute it so frequently ; and if its proposers
would only study some elementary work on mechanics and
calculations on specific gravity, &c., they would themselves see
the absurdity of their propositions.

Then there are a number of re-inventions and bright ideas
that strike men of all classes and in all lands, who are con¬
tinually writing to members of our Society, and especially the
“Noble Dukes,” announcing that they have “solved the
problem,” and expecting untold gold to result therefrom; but

AERONAUTICAL SOCHTTY

when the happy interview takes place it is found that they do
not even know the pressure of the air at 10 miles . an hour, the
weight of a cubic foot of air, of a cubic foot of hydrogen or coal
gas, or even a cubic foot of water, and as to the cubical contents
of a balloon or the oost of the silk they are equally innocent ;
and although our Reports have been published for 10 or 11
years, these Gentlemen utterly ignore those Reports, and
persistently think that their ideas are new as well as good.

There are only a few modes of procedure to choose from.
Balloons being the oldest we will begin with them. I will
take three of Mr. Coxwell’s balloons as examples.

1. — The Express, 48ft. diameter, contains 60,000 cubic
feet of gas, and will accommodate 7 persons.

2. — The Nassau, 52ft. diameter, oontains 80,000 cubic
feet of gas, and will accommodate 12 persons.

3. — The Research, 60ft. diameter, contains 120,000 cubic
feet of gas, and ‘will accommodate 15 persons.

This is with common coal gas at, say, 3s. 6d. per thousand
cubic feet.

These three balloons give an idea of size and cubical
contents suitable for ordinary purposes.

Supposing, then, that a balloon is selected as the subject
of experiment, and that you choose a somewhat smaller size,
say 30ft. diameter, a globe as here shown on a scale of half-an-
inch to a foot. You have a variety of aeriform fluids from which
to choose in order to fill it and make it aseend ; but bear in mind
that you can never make it anything else than a drifting
machine. You may try to make it a model of the planet
Saturn ; you may put to it any amount of sails or other
gimcracks ; but it will remain nothing else than a drifting
machine, able only to ascend, descend, and drift with the wind.

You may take up with another old idea and give it this
form — indicated on the black-board — The globe would take

OB’ GREAT BRITAIN.

320 square yards of silk, and would contain 14,000 cubic feet
of gas, and would displace balf-a-ton of air ; but tbis, of 30ft.
diameter and 120ft. long, would contain 77,000 cubic feet of
gas, and would require 1,260 square yards of silk, the dis¬
placement of air being 2| tons. Here you have a little
scope for a very gentle propulsion in calm air, but it is
only a little less a drifting machine than the globe. You
might carry up two aeronauts and a screw propeller, and do
a little feeble work, but it is useless to expect much from this
form. It also introduces a new element of difficulty — it requires
stiffening. This, of course, adds very much to the loss of
buoyancy, as you have of necessity added to the weight of
materials ; and in order to drive this dt only 5 miles an hour
in still air you would reqhire an engine of at least 3-horse power.

But in order to reduce the resistance still further you may
adopt this form — indicated on the black-board — You gain in
speed but lose in buoyancy, because of the framing. This
has a similar diameter, 30ft., and displacement 3f tons, but
is 184ft. long. 2-horse power would drive this at 5 miles an
hour in still air, but it would require a very careful design to
make it succeed, and it might possibly be made for £500.
or £600.

Now these three forms are all very useful for drifting or
travelling very slowly in a calm, but as we cannot abolish wind
the wind tnust be encountered ; and as it so happens that with
aeroplanes, unsupported by bulky gas, high speed means
economical travelling, most of our Members have come to the
sensible conclusion that aeroplanes, properly balanced and
driven by steam or other motive power, afford the best means
of working out this interesting problem.

I have heard, very lately, from those who have travelled
in the Arctic regions, that there is very little wind there in
the summer. If this is so there would be no serious difficulty

AERONAUTICAL SOCIETY

in constructing an aerial vessel of the form shown by No. 3,
and folding it up lengthwise on the deck of a vessel. When
the vessel had got as far North as practicable this vessel could
be inflated, the engine and propellers attached, and it could
certainly be driven at from 10 to 20 miles an hour, and come
back to the ship with as much precision as any ordinary steam
launch can be managed. I make this exception when I call
these drifting machines ; and the mere fact of such a vessel
going 800 miles in the Arctic regions would not deter one
Member of this Society from pursuing his work on aeroplane
machines, which will dispense with gas or other fluid altogether.

I could not go into the subject of aeroplanes without
repeating what has been already published in our Reports, and
that would be a waste of your time.

I have been unable to construct any practical machine
since my well-known experiments 2 years ago, and must wait
until I have means and opportunity. I have some very care¬
fully matured plans which I hope some day to put into
practice ; and I should be very happy to contract with our
Government to fix the British flag where the North Pole is.
or ought to be, for a very much less sum than that which
was expended on the last Arctic Expedition.

The Chairman : Has any gentleman any remark to make
upon the Paper we have just heard. I think the simplest way
of stating the floating power of a balloon is that 1,000ft. of
gas will lift about 401bs., the gas being the average gas we
are using — 14-candle gas. As to the advantages of a fish¬
shaped balloon, I do not quite agree with Mr. Moy, though we
might have power to move with great facility. The advantage
of the globular balloon is that we have to use less material,
and at present I am inclined to think that the globular form
is the best for most purposes. Mr. Moy says “ that with the

OP GREAT BRITAIN.

fish-shaped balloon we could deviate several degrees to the
right or to the left ; ” but I have never been able to satisfy
myself that the fish-shaped balloon would succeed. As regards
ie balloon I am afraid that it cannot be made to deviate much
from the direction in which the wind is moving, and I see no
means of controlling or evading that strong and great power,
the wind — a power for which most aeronauts who have been
under its influence, and have had rough descents, will have a great
respect. I think our object should be to make some experi¬
ments on aerial planes, and if we do not get the knowledge we
seek we shall certainly get something that will repay our
trouble. If the experimenter does not succeed in the direction
in which he hopes for success, he will probably be recompensed
for his time and trouble by the knowledge acquired through
the experiments themselves. I have now to ask you to thank
Mr. Moy for the Paper he has just read.

Mr. Moy : M. de Lome took up a few men to work his
cranks and screw propeller. My engine weighed 801bs. and
exerted 3-horse power ; therefore if M. de Lome had taken my
engines he would have done much better.

The Chairman : He did not know your engines. It is a
pity that he did not.

Thanks were accorded to Mr. Moy.

Mr. Moy : I must do the same as Mr. Brearey, and thank
you for your thanks.

The Chairman : Ladies and Gentlemen, my agenda paper
is exhausted, and happily in good time, for I feel that in
meetings like this we all regret the approach of ten o’clock.
I have only now to adjourn this Meeting, but I have no doubt
that new matter will be collected and further information sent
out to you with the Annual Report. I thank you very much for
the kind attention you have given to the Papers, and hope our
Members will give us the benefit of their further researches,

AfooXAUTIOAL SOCIETY.

and trust that many investigations and experiments may be
made, and the results of them may be communicated to our
Society.

Mr. Lefeuvbe : I hope this Meeting will not separate
without giving a vote of thanks to the Chairman. I can bear
testimony to the great interest he has shown in this Society on
all occasions, and I was well pleased to see him in the Chair.
Our Secretary is a most untiring Secretary, and I hope, "with
such a Chairman and such a Secretary, before we meet again
we shall be able to put before you most interesting facts.

The motion was carried by acclamation, and the Chairman
having acknowledged the compliment the Meeting separated.

In accordance with the expressed intention to reprint any
matter of interest which might be otherwise unattainable, so that
in process of time everything worth knowing upon the subject of
Aeronautics might be included in our Annual Reports, we now
present a Pamphlet, published in the year 1810,% Thos. Walker,
of Hull, which, by the kindness of Edward Bannister, Esq., J.P.,
of Grimsby , was lent to the Secretary.

The publication of this Pamphlet was a matter of history,
but it was not known whether a copy was in existence.

TREATISE

UPON THE

ART OF FLYING,

BY MECHANICAL MEANS,

WITH A

FULL EXPLANATION OF THE NATURAL PRINCIPLES
BY WHICH BIRDS ARE ENABLED TO FLY;
LIKEWISE

INSTRUCTIONS and PLANS,

FOE MAKING A FLYING CAE WITH WINGS, IN WHICH A MAN MAY
SIT, AND, BY WOBKING A SMALL LEVEE, CAUSE HIMSELF TO
ASCEND AND SOAB THEOUGH THE A IE WITH THE
FACILITY OF A BTftD.

By THOMAS WALKER ,

PORTRAIT PAINTER, HULL.

HULL:

PRINTED BY JOSEPH SIMMONS, AT THE ROCKINGHAM OFFICE;
AND SOLD BY LONGMAN, HURST, REES, & ORME, LONDON;
AND BY ALL THE PRINCIPAL BOOKSELLERS IN
TOWN AND COUNTRY.

1810.

TO THE

Right Hon. Earl STANHOPE.

My Lord,

As far as an obscure individual like myself can judge
of exalted characters, I am induced, in unison with public
opinion, to hold a belief that your lordship is possessed, in a
very superior degree, both of genius and a knowledge of the
sciences, as well as a known predilection for every thing that is
calculated to improve and extend the mechanic arts, or to
meliorate the condition of mankind.

To acknowledge also that your lordship is equally pre¬
eminent in the senate is but paying a tribute which is very
justly due to your patriotism, and the great exertions which you
have made in advocating the cause of humanity. Every friend
to his country must hold in grateful remembrance the energetic
and manly opposition which your lordship evinced to prevent
the commencement of a war more undefined in its object, more
inefficient, and more direful and ruinous in its consequences to
our country than any war it was ever madly and unjustly
plunged into.

My countrymen have now great cause also to remember,
with indignation and deep regret, that, in return for your
opposition to the origin of those baneful effects, which your
lordship clearly foretold, and are now but too severely felt ; in
return for your wise counsels and patriotic zeal, your lordship
met with every coarse insult and contumely which blind folly

TREATISE UPON THE AET OF FLYING.

and malice could suggest. But your lordship has this inestim¬
able consolation, that your life has been most honourably
engaged — not with the savage arts of murder ; not with the
burning of towns and the destruction of their unoffending and
defenceless inhabitants ; not with the filling of Europe with
miserable widows and orphans ; not with the ruin of manu¬
factures and commerce, and the violation of the sacred
constitutional rights and liberties of your countrymen ; not
with the low, base, and contemptible arts of any corrupt and
venal faction ; not with the arts of tyranny and oppression, or
force and fraud ; not with the machiavelian arts ; but with the
noble arts which are conducive to peace, civilization, and the
convenience and happiness of mankind.

Had I invented a diabolical engine that would effectually
have swept off from the earth a considerable portion of its
unwary inhabitants, I should never have thought of addressing
your lordship ; I must have sought patronage from another
quarter ; but, considering the subject of this work, I thought
no one was more able than your lordship to form a just
estimation of its merits. I have, therefore, taken the liberty
of dedicating it to you, flattering myself that the theory it
contains will be honoured with your lordship’s approbation,
which will greatly contribute to the pleasuve of,

My Lord,

Your Lordship’s humble Servant,

Hull, Feb., 1810.

THOMAS WALKER.

PREFACE.

J AM laying before the public a treatise upon a subject
perhaps as extraordinary in its nature as anything
that has lately come before them ; and after a candid perusal,
should it meet with approbation from the friends to arts and
sciences, my utmost pride will be gratified. The flight of birds,
although so common and familiar to our sight, is certainly as
great a phenomenon as any in the creation ; and artificial
flying, when accomplished, may be considered as one of the
greatest wonders of the mechanic arts, which I firmly believe
attainable upon the plan I have suggested.

In this little work I have shown that birds’ wings do not
increase their expansion in exact ratio with the increased
specific gravity of their bodies ; I have given a demonstration
of the cause of the projectile motion of birds, the discovery of
a true knowledge of which has bid defiance to philosophers in
all ages, which, with other discoveries, I trust will prove that I
have given consistency to what henceforth may be denominated
the science of flying, and which may alone be deemed of con¬
siderable importance to science, had nothing more than that
been brought forward ; but as I have gone much further, and
have advanced arguments, and given plans to render the art
of flying practicable, the importance of this little treatise
becomes obvious, more particularly so if we take into
consideration the various purposes to which artificial flying
may be applied.

TREATISE UPON THE ART OF FLYING.

When my work was just ready for the press, I was much
surprised at the account a friend gave me of what he had seen
that day upon flying, in a monthly journal. I immediately
procured a sight of it, and found it to be an ingenious paper
written by Sir George Cayley, and I own I was astonished at
the perusal. I conceived it to be very extraordinary that two
persons, not having the least knowledge of each other, should
be publishing their thoughts at the same time upon such a
subject ; nor was I less surprised to find the subject treated of
there in a manner so rational and far superior to anything I
had ever seen before. From what Sir George has thought,
and the calculations he has made upon the subject, he is so
sanguine in his belief that flying will be effected as to say, in
one part of his paper, as follows : — “ I feel perfectly confident,
“ however, that this noble art will soon be brought home to
“man’s general convenience, and that we shall be able to
“ transport ourselves and families, and their goods and chattels,
“ more securely by air than by water, and with a velocity of
“from 20 to 100 miles per hour.” — Vide Nicholson’s Journal
for November, 1809.

For my own part, whatever reason I may have to be
sanguine of success, I have made a resolution to suppress in my
work every thought that confidence could suggest beyond what
I could give demonstration of, along with the clearest directions
how to attain the end in view ; thereby putting it out of the
power of critics to say that the principles of my theory have
not a good foundation.

Notwithstanding, from the novelty and' singularity of the
subject, I do expect to meet with a good deal of raillery and
sarcasm. The wits will tell me that I am flighty, and the
more serious and heavy part of mankind, who are too ponderous

TREATISE UPON THE ART OP FLYING.

for such aerial flights, will express a disapprobation of mj
scheme ; but I do not write for such folks, mj sole aim is to
deliver my thoughts to the public, in hopes that men of genius
and science may turn their attention to a subject that may not
before now have attracted their notice, that, by their aid and
assistance, the art may be brought into practice ; and, as this
country stands unrivalled in arts, I hope we shall not be long
without a Society for the encouragement of the art of flying.
Columbus was laughed at when he talked of a continent beyond
the Atlantic ; but flighty as he might appear he found it, and
wise men lost it !

A TREATISE, &c.

"^/"E learn, from several authors, that, in different ages
of the world, the art of flying has been attempted
by various means, all of which have hitherto failed of
success. When we take into consideration the different
methods which are recorded to have been tried, we cannot be
surprised that they have all failed, since, compared with what
is contained in the following pages, they will obviously appear
to be nothing more than mere whims and contrivances, all
utterly destitute of the true nature and science of flying.

I am conscious that many of my readers, who have
never been led to notice the remarks that many eminently-
learned men have made upon this art, will be tempted at the
first sight of my title page to ridicule a treatise upon artificial
flying ; for there is not a more common saying, when a person
has taken some great difficulty in hand, than that such a thing
is as impossible to be done as for one to fly in the air. I do
assure all such that my treatise is not founded upon a whim of
the moment, but from mature deliberation on the display of
nature. The study of the works of nature has been to me,
during the greatest part of my life, a source of amusement and
inexpressible delight. The natural history of birds has par¬
ticularly occupied my attention, and that enviable faculty which
they possess of flying, has greatly excited my curiosity, and led

TREATISE UPON THE ABT OF FLYING.

me to that study by which I have obtained a true knowledge of
the mechanical principles by which they fly, a knowledge which
I do not hesitate to declare has hitherto remained undiscovered,
although it has been the object of the study and contemplation
of many of the most eminent philosophers of past ages.

That great observer of the works of nature, Solomon, did
not overlook the subject of flying, but speaks of it in his book
of Proverbs, xxx, 18, 19 — “There be three things which are
“too wonderful for me, yea four, which I know not : the way
“of an eagle in the air, the way of a serpent upon a rock,” &c.
I beg also to remind such of my readers as doubt the possibility
of flying that many useful and valuable mechanical inventions,
which are now complete and become common, would, a century
or two past, have been treated as visionary or impracticable ;
or- had they been accomplished at such periods their effects
would have been attributed to witchcraft. I have not the least
doubt of being successful in the art of flying, if I had it in my
power to give it a fair trial. My invention for attaining the
art is founded entirely upon the principles of nature ; and
although these principles are as old as the creation, they have
never, until now, been properly attended to. How much are
we indebted to the study of nature for discoveries of the greatest
importance ? and from this delightful study many more are yet
to be expected.

The love of pleasure is natural to man, and to gratify this
propensity he eagerly attends to every artificial entertainment
that is offered to him. He resorts to theatres and operas,
to Newmarket, and other haunts of vanity and folly, as if
pleasure were nowhere else to be found ; at the same time
what an inexhaustible fund of entertainment is overlooked by
all but a few, although constantly displayed in the wonderful
exhibition of the works of nature.

TREATISE! UPON THE ART OF FLYING.

What a pity it is that minds of men are not more generally
and forcibly struck with the pure and tranquil delights resulting
from the universal study of nature. What riot, confusion,
waste of time, loss of money and of health, might be avoided
if this pleasing and truly-enlightening study could be made
fashionable. What an infinite stock of ideas it would create ;
how much it would enrich the human mind, and afford matter
for social conversation and entertainment far superior to the
unimportant subjects which too generally occupy the minds.and
tongues of men.

I will now present my readers with some account of
various schemes which have been tried to accomplish the art
of flying, and shall show the cause of their insufficiency. I
shall explain the natural mechanical means by which birds .are
enabled to fly, and my readers will then be able to judge how
far my invention for flying corresponds with the natural science,
and is thereby calculated to succeed. I shall show likewise
the comparative difference between the specific gravity of the
humming bird and the condor, also the different expansion of
the wings. I shall compare the weight of a man with the
weight of the condor, and thereby determine the necessary
dimensions of a pair of wings which would enable a man to fly ;
and, lastly, I will explain an experiment which I have made, in
order to demonstrate the principles of artificial flying, and give
directions for making a machine wherein a man may sit, and,
by working a pair of wings with a lever, be able to ascend into
the air, and fly with as much safety and ease as a bird.

During the early part of my life I have dissected a great
many birds, and since studied very minutely the mechanism of
their wings, tails, and all the parts which they employ in flying.

TREATISE UPON THE ART OF FLYING.

I have long been accustomed to contemplate a bird as a
living machine, formed by the Almighty creator, either to run
upon the earth, to dive in the waters, or to ascend into or fly
through the air ; and when I examine its various parts, and
find such an exquisite display of wisdom in each being formed
so perfectly to answer the use it is applied to ; when I see the
effect of the whole, that such a wonderfully-organized animated
piece of matter can quit the earth and soar aloft in the air,
it appears to me a miracle, and I am struck with admiration.

It is now almost twenty years since I was first led to think,
by the study of birds and their means of flying, that if an arti¬
ficial machine were formed with wings, in exact imitation of the
mechanism of one of those beautiful living machines, and
applied in the very same way upon the air, there could be no
doubt of its being made to fly ; for it is an axiom in philosophy
that the same cause will ever produce the same effect.

It is easy to demonstrate that a bird is no more able to
fly than a man without the mechanical effect of wings ;* there¬
fore, when a man is furnished with p, pair of wings large enough,
and can apply them in the same manner as a bird does, and
with sufficient power, there can be no reason to doubt of a man
being able to fly as well as a bird. The machine which I have
planned is as close a copy of the natural mechanism of a bird

* The ostrich, in the torrid regions of Africa ; the emu, in the
extensive plains of Paraguay, in South America, which, standing erect,
is about seven feet high, it legs are three feet long, its thighs are nearly
as thick as the thighs of a man, it runs so swift that the fleetest dogs are
foiled by it ; the cassowary and the dodo, in the Molucca Islands ; and
the penguins, in the Straits of Magellan and the South Sea Islands. All
these birds are as utterly incapable of flying as a man, none of them
being provided with wings for that purpose.

tbeatibe upon the abt of flying.

as artificial means will admit of ; and when my readers are
made thoroughly acquainted with both the natural and artificial
means of flying, I flatter myself they will then be willing to
acknowledge that my scheme is a very rational one, highly
calculated to insure success in the accomplishment of the art
of flying, one of the most extraordinary and desirable arts with
which we dfo be acquainted.

Although I have, for many years, been extremely anxious
to bring the machine into effect, and am very sanguine in my
expectations of success (for I positively assert that flying cannot
be accomplished on any other plan than the one X propose), I,
unfortunately, have ever found myself unable, from my pro¬
fessional avocations and other circumstanoes, to put it in
practice, or I should long sinoe have made the experiment.

Finding, therefore, that to no purpose I have deferred, for
a long time, its execution, which I deeply regret, and the
prospect of the future being not more favourable, I am induced
to publish my plan, in the hope that the lovers of the arts and
sciences, when I have laid before them a scheme so practicable,
will readily be induced, for the honour of science and our country,
to contribute to the mdtas of bringing it into practioe, and
demonstrate to their fellow mortals how they may gain a
perfect dominion over another element.

In almost every nation where arts and sciences have
flourished, persons have manifested a wish to discover the art
of flying. In Eome and in Paris particularly different persons,
and in ages remote from each other, have tried experiments
with wings formed of various materials, which have been
fastened to their arms, but none of them succeeded, there not
being strength sufficient in a man’s arms to enable him to fly

TREATISE UPON THE ART OF FLYING.

with detached wings fastened to him, leaving the whole weight
of his body unsupported.

Friar Bacon, who lived nearly five centuries ago, wrote
upon the subject, and he affirms that the art of flying is
possible ; and many others have been of opinion that, by means
of artificial wings affixed to the arms or legs, a m£n might fly
as well as a bird.

The philosophers of the reign of King Charles the Second
were much engaged with this art. The famous Bishop Wilkin,
who, in 1672, published a treatise upon flying, was so confident
of its practicability, that he says he does not question but that
in future ages it will become as common to hear a man call for
wings when going a journey as it is now to call for his boots
and spurs.

In the year 1709, as we gather from a letter published in
France in 1784, a Portuguese, Friar de Gusman, applied to the
king to encourage him in the invention of a flying machine.
The principle upon which it was constructed, if indeed it had
any principle, seems to have been that of a paper kite. The
machine was in the form of a bird, and contained several
tubes through which the wind was to pass in order to fill a
certain sail, which was to elevate it ; and when the wind was
deficient the same was to be effected by means of bellows
concealed within the body of the machine. The ascent was
also to be promoted by the electric attraction of pieces of amber
placed in the top, and by two spheres inclosing magnets in the
Bame situation.

These silly inventions show the very low state of science
at that time in Portugal, especially as the king, in order to

TREATISE UPON THE ART OF FLYING.

encourage him in his further experiments in such an useful
invention, granted him the first vacant place in his College of
Barcelos or Santerim, with the first professorship in the
University of Coimbra, and an annual pension of 600.000 reis
during his life. Of this De Gusman it is also related that, in
the year 1736, he made a wicker basket of about seven or eight
feet diameter, and covered it with paper, which raised itself
about 200 feet in the air, and the effect was generally attributed
to witchcraft.

Mr. Willoughby, after observing that the pectoral muscles
of a man, in proportion to his weight, are many degrees too
weak for flying, recommends to him who would attempt the
art with the desire of success to contrive and adapt his wings
in such a manner that he may work them with his legs and
not with his arms, because the muscles of the legs are much
stronger.

The celebrated Lord Bacon wrote on the subject of flying,
and believed it practicable, but it seems he could no more direct
how.it was to be done than any other who had written before
him on the same subject.

Thus much, for the satisfaction of my readers. I have
thought proper to make mention of what has been attempted
in the accomplishment of this wonderful art ; but were I to
adduce all that has been said and done, at different periods of
time, I could compile a large volume of that alone, which
would answer no other end than that of curiosity, and to show
that no one has ever understood the natural means of flying,
which is the only knowledge that can guide us to the completion
of artificial flying, and which I hope and trust will be clearly
demonstrated in this treatise.

TREATISE UPON THE ART OF FLYING.

As I shall have occasion to refer to various birds, possessing
different powers of flight, in illustration of my design, I here
introduce the history of the condor, for the information of such
of my readers as may not be acquainted with it.

The condor is a native of America, and hitherto naturalists
have been divided whether to refer it to the species of the eagle
or to that of the vulture. Its great' strength and activity seem
to give it a claim to rank among the former, whilst the bald¬
ness of its head and neck is thought to degrade it to a rank
amongst the latter. It is, however, fully sufficient for our
plan to describe its manners, form, weight, expansion, and
power ; we will therefore leave to nomenclators to decide upon
its class. If size (for it is by much the largest bird that flies)
and strength, combined with rapidity of flight and rapacity,
deserve pre-eminence, then no bird can be put in competition
with it ; for the condor possesses, in a higher degree than the
eagle, all the qualities that render it formidable not only to
the feathered tribe, but to beasts, and even to man himself.

Acosta, Garcilasso, and Desmarchais assert that it measures
eighteen feet across the wings when expanded ; its beak is so
strong as to pierce the body of a cow ; and it is positively
asserted that two of them are capable of devouring that
animal. They do not even abstain from attacking man him¬
self ; but, fortunately, there are but few of the species. The
Indians say that they will carry off a deer or a young calf in their
talons as an eagle would a hare or rabbit, that their sight is
piercing, and their manners terrific. According to modern
authors they only come down to the sea coast at certain seasons,
particularly when it is supposed their prey fails them upon the
land ; that they then feed upon dead fish and such other
nutritious substances as the sea throws upon the shore.

TREATISE UPON THE ART OF FLYING.

Condamine says he has frequently seen them in several
parts of the mountains of Quito, and has observed them hovering
over a flock of sheep ; and he thinks they would, at one par¬
ticular time, have attempted to carry some of them off had
they not been scared away by the shepherds. Labat says that
this bird has been described to him, by those who have seen
it, as having a body as large as a sheep, and that its flesh is as
tough and disagreeable as carrion. The Spaniards residing in
that country dread its depredations, there having been many
instances of its carrying of children. Mr. Strong, the master
of a ship, relates that, as he was sailing along the coast of
Chili, in the thirty-third degree of South latitude, he observed
a bird sitting upon a high cliff near the shore, whioh one of
the ship’s company shot with a leaden bullet and killed. They
were greatly surprised when they beheld its magnitude, for
when the wings were extended they measured thirteen feet
from one tip to the other ; one of the quill feathers was two
feet four inches and three-quarters in length, and an inch-and-
a-half in circumference.

Mons. Feuillee, whose description alone is accurate, has
given a still more circumstantial account of this amazing bird.

' “In a valley of Illo, in Peru,” says he, “I discovered a
condor perched on a high rock before me. I approached within
gun-shot and fired, but as my piece was only charged with
swan-shot the lead was not heavy enough to bring the bird
down. I perceived, however, by its manner of flying, that it
was wounded, and it was with a good deal of difficulty that it
flew to another rock about 500 yards distant on the seashore.
I therefore charged again with the ball and hit the bird under
the throat, which made it mine. I accordingly ran up to seize
it ; but even in death it was terrible, and defended itself upon

TREATISE UPON THE ART OF FLYING.

its back with its claws extended against me, so that I scarcely
knew how to lay hold of it. Had it not been mortally wounded
I should have found it no easy matter to take it, but I at last
dragged it down from the rock, and, with the assistance of one of
the seamen, I carried it to my tent to make a coloured drawing
of it. The wings of this bird, which I measured very exactly,
were twelve feet three inches (English) from tip to tip. The
great feathers, which were of a beautiful shining black, were
two feet four inches long. The thickness of the beak was
proportionable to the rest of the body, the length about four
inches, the point hooked downwards and white at its extremity,
and the other part was of a black jet. The thigh bones were
ten inches long, the legs five inches, the toes and claws were
in proportion, and the legs were covered with black scales. The
little nourishment which these birds find on the coast, except
when a tempest throws up some great fish, obliges the condor
to continue there but a short time. They usually come to the
coast at the approach of evening, stay there all night, and fly
back in the morning.”

I now proceed to describe the construction and application
of the wings of a bird. How properly are they formed to fulfil
the uses they were made for ! The first is to expand, and by
that means to give the bird a secure hold upon the air below
it, which hold is always in proportion to the dimensions of the
wings. The tail produces the same effect. We see that by
means of a pair of wings and a tail duly expanded, in a perfectly
passive state and aloft in the air, without any muscular motion,
a bird procures a suspending power, which counteracts the
specific gravity of its body, and prevents it being precipitated
to the ground ; such is the effect of the wings and tail when
in a passive state.

TREATISE UPON THE ART OF FLYING.

4/j

I will next take some notice of the quill feathers, which
are replete with proofs of the wisdom of the Almighty artist
who made them. As they were intended to swim within so
light and subtle a fluid as the air is, it was necessary that they
should be formed of the lightest materials imaginable ; and as
they were intended to strike upon the air with great power and
rapidity, it was requisite that they should possess in the shafts
great strength with elasticity ; it was expedient too that the
quill feathers should separate and open to let the upper air
pass through the wings, to facilitate their ascent when they
are struck upwards ; it was also necessary that they should all
shut close together, forming each wing into a complete surface
or web, when they are, by the muscular power of the bird,
forced down in order to give a more secure hold upon the air
below, and by that means keep the bird up.

Now if we do but examine the quill feathers we shall
find in the shafts astonishing strength with elasticity, and very
little specific gravity indeed. The webs of the quill feathers are
broader on one side of the shaft than the other, which causes them
to open as the wings move up and to shut as they come down,
exactly answering the purposes I have already mentioned ;
therefore, we see how wonderfully-complete the wings are in all
their parts, and how effectually they serve all the uses required.

I will now show the application and effect of the wings
and tail in an active, state. When a bird, by the power of its
pectoral and deltoid muscles, puts its wings into action and
strikes them downwards in a perfectly vertical direction upon
the air below, that air being compressed by the stroke of the
wings makes a resistance, by its elastic power, against the under
side of the w’ings, in proportion to the rapidity of the stroke
and the dimensions of the wings, and forces the bird upwards ;

TBEATI8E UPON THE ABT OP FLYING.

at the same time, the back edges of the wings beings more
weak or elastic than the fore-edges, they give way to the
resisting power of the compressed air, which rushes upwards
past the same back edges, acting against them with its elastic
power, and thereby causes a projectile force, which impels the
bird forwards ; thus we see that by one act of the wings the
bird produces both buoyancy and progression. When the tail
is forced upwards, and the wings are in action, the bird ascends,
and forced downwards it consequently descends ; but the most
important use oj the tail is to support the posterior weight of the
bird, and to prevent the vacillation of the whole.

Thus having discovered and explained to my readers the
natural mechanical means by which birds accomplish flying,
they will be able to see that the plan upon which I have formed
my scheme for artificial flying is perfectly analagous to the
principles of nature, which certainly ought to be clearly under¬
stood, and taken as our only guide, before we can ever expect
to arrive at success in the art of flying ; but with the knowledge
of these principles there' cannot remain a doubt of success.

When we first think of a man attempting to fly by
mechanical means, we are induced, considering his specific
gravity to pronounce it impossible ; and had we never seen or
known of any bird larger than a humming bird, whose weight
does not exceed one drachm, and whose diminutive wings
measure only three inches from tip to tip ; and wero to be told
by some traveller that he had seen a bird with a body as large
as a sheep, that had wings of twelve feet expansion, and that
it could quit the earth and ascend into the air with its ponderous
body, and there fly about with as much ease as the little hum¬
ming bird, we should think it too marvellous a tale to be
credited. But as we are accustomed to see, almost every day,

TREATISE UPON THE ART OF FLYING.

birds of such various dimensions and specific gravity as are
exhibited by nature, from the humming bird to the common
wren ; from the wren, through a numerous gradation, up to
the eagle, we can readily give credit to the history of the
wonderful condor in South America, whose existence is so well
attested that we can have no reason to doubt of it, more
especially as we witness so vast a gradation in the indigenous
birds of our own country. I believe that there, were two of
these prodigious birds in the Leverian Museum.

The following observations upon the wonderful difference
in the weight of some birds, with their apparent means of
supporting it in their flight, may tend to remove some
prejudices against my plan from the minds of some of my
readers. The weight of the humming bird is one drachm, that
of the condor not less than four stone. Now, if we reduce four
stone into drachms, we shall find the condor is 14,336 times
as heavy as the humming bird. What an amazing dispropor¬
tion of weight ! Yet, by the same mechanical use of its wings,
the condor can overcome the specific gravity of its body with
as much ease as the little humming bird. But this is not all.
We are informed that this enormous bird possesses a power in
its wings, so far exceeding what is necessary for its own
conveyance through the air, that it can take up and fly away
with a whole sheep in its talons, with as much ease as an eagle
would carry off, in the same manner, a hare or a rabbit. This
we may readily give credit to, from the known fact of our little
kestril and the sparrow hawk frequently flying off with a
partridge, which is nearly three times the weight of these
rapacious little birds.

Let us attend to this subject a little further. Let us
consider these wings of the condor, which, with a mechanical

TBEATI8E VPOlf THE ABT OF FLTTNO.

action alone, produces a power that is capable of carrying
through the air both the bird and the sheep, weighing together
not less than ten stone, which would then be 204,000 times the
weight of the humming bird! When this is duly considered,
with reference to my plan, what encouragement does it not
give to prosecute the art of flying ? particularly so when we
consider that a man of ten stone weight, in a machine weighing
two stone, will only exceed the weight of the condor one-fifth
part; this is a mere trifle compared with the astonishing
difference there is between the humming bird and the condor.

The condor carries ten stone, with wings of twelve feet
expansion from tip to tip; the humming bird carries one
drachm, with three inches expansion ; the common wren is
three times as heavy as the humming bird, and has but one
inch more of wing; a pigeon weighs 16 ouncls. which is 256
times as heavy as it is, and has only ten times more expansion
of wing ; the goatsucker is forty times as heavy, and has seven
times the length of wing. I could bore carry the same
observations upon other birds to a very great extent, but the
above are instances sufficient to prove that birds’ wings are not
multiplied in their length in the same proportion with the
increased weight of their bodies : therefore, as a man weighing
ten stone and his machine two, as I have already shown, will
only exceed in weight one-fifth part of the weight of the
condor and his prey ; and as the wings of the condor are about
twelve feet, suppose we make a pair of wings of silk, one-fifth
longer than they are, which will be about fourteen feet and a
half, I am thoroughly persuaded they will be found amply
sufficient, as they will far exceed the progressive increase of
birds’ wings.

By attending to the progressive increase of the weight of

TREATISE UPON THE ART OF FLYING.

birds, from the delicate little humming bird up to the huge
condor, we clearly discover that the addition of a few ounces,
pounds, or stones, is no obstacle to the art of flying ; the
specific weight of birds avails nothing, for by their possessing
wings large enough, and sufficient power to work them, they can
accomplish the means of flying equally well upon all the various
scales and dimensions which we see in nature.

Such being a fact, in the name of reason and philosophy
why shall not a man with a pair of artificial wings, large
enough and with sufficient power to strike them upon the air,
be able to produce the same effect.

I shall, after a few observations, proceed to describe how
a machine may be made with a pair of wings, and a lever to
work them with, so that any person will be able to see how far
it is calculated to answer the purpose for which it is intended.
This machine may be considered as a large artificial bird, and
the man placed in the inside as the vital or moving power.
All the attempts hitherto made in the art of flying, by different
persons, according to historians, have been mere childish whims,
not in the least degree calculated to insure success. They each
made a pair of detached wings, some of silk, some of leather,
and 'some of sheet iron and various other materials ; they
fastened them upon their shoulders or arms : thus equipped,
they placed themselves upon some eminence, such as a high
tower or a church steeple, then took to their wings ; but few of
them were fortunate enough to escape without some injury.

It is utterly impossible for a man to fly with a pair of
wings fixed to his shoulders or arms, with the whole weight
of his body hanging down and depending entirely on his
pectoral muscles for support. These muscles in a man are

TREATISE UPON THE ART OF FLYING.

many degrees too weak to keep extended a pair of wings of
sufficient expansion to effectually counteract the specific gravity
of his body. Let a man suspend the weight of his body, with
his arms extended, holding to an horizontal beam by his hands,
and he will very soon find the insufficiency of the strength of
his arms to support his weight. On the plan which I have
conceived for flying the want of strength in the arms is amply
provided for. By furnishing a man with a car to sit in, the
whole weight of his body is supported by it, and as he sits
much in the same manner as if he were rowing a boat, he is
enabled to bring into action his whole bodily strength, which
far exceeds the strength of his arms only, and by sitting in such
a position his strength can be exerted with a far greater force
than in any other attitude whatever ; he at the same time
gains an additional advantage, in this plan of mine, by exerting
his strength upon a lever.

The two greatest requisites for accomplishing the art
of flying are these — first, expansion of wings large enough to
resist, in a sufficient degree, the specific gravity of whatever is
attached to them ; second, strength enough to strike the wings
with a sufficient force to complete the buoyancy, and give a
projectile motion to the machine. With these two requisites
combined flying must be accomplished; and, upon my plan,
there can be no doubt of wings being made as large as ever
they may be wanted ; neither ought we to doubt of a man’s
ability, exerting himself in the way I have described, to bring
into action as great a degree of strength, in proportion to his
weight, as the condor is possessed of. Therefore, if we are
secure of these two requisites, and I am very confident we are,
we may calculate upon the success of flying with as much
certainty as upon our walking.

TREATISE UPON THE ART OF FLYING.

When I first thought of artificial flying, it occurred to me
that it would be of some importance to try what effect a pair
of wings would have upon the air, without any mechanical
power to work them ; I thought that if I were to suspend a
weight from beneath them, and they should prevent that
weight fTom falling in a perpendicular line to the ground, they
would demonstrate that the ideas I had conceived of the cause
of the projectile motion of birds were well founded.

I therefore made the following experiment, to which I call
the particular attention of my readers, as it positively demon¬
strates the cause of the projectile motion. I made a pair of small
wings, of fine paper, and very small slips of wood to keep them
extended, and fixed on a tail of the same materials, imitating,
as near as I could, the wings and tail of a bird when expanded
in a passive state. I then suspended a small weight from under
them, with a piece of thread, exactly in the centre of gravity ;
I held them up as high as I could reach, then took away my
hand and left them flat upon the air, without giving any
impulse to them whatever ; and by the weight pressing down¬
wards the air under the wings became, in some degree,
compressed, and by its reaction against the under side and
the back edges of the wings, they were projected with an oblique
descent from one end of the room to the other, carrying the weight
all that distance, which, without the wings being of this par¬
ticular construction, could not have been done.

I had cause sufficient to exult in the success of my
experiment, which proved to me, in a very satisfactory manner,
that what I had conceived to be the cause of the projectile
motion of birds was really the cause, and that if I could but
give a vertical motion to the wings, so that they might strike
upon the air with a sufficient force, they would then increase

TREATISE UPON THE ART OF FLYING.

the reaction of the air, and instead of being projected in an
oblique descent, totally overcome their specific gravity, and
continue flying in an horizontal direction.

This is an experiment which any of my readers may make
trial of for their own satisfaction and amusement.

Another experiment, serving to shew the different effect
of buoyancy obtained by a parachute and by my paper wings,
may be tried in the following manner : — Take two straight
sticks, neatly dressed, about the thickness of a crow-quill, and
each about sixteen inches long, lay them across each other in
the middle, at right angles, and tie them fast with a piece of
thread ; then tie a piece of thread from the ends of one stick
to the other, so as to secure them at right angles ; then take
a sheet of gauze paper, and fasten all the four corners of it to
the four ends of the sticks ; but previous to this, paste upon
the four corners of the paper four small slips of thin cloth, in
order to give sufficient strength ; then suspend any small weight
by a thread from the centre ; let the whole fall from a height,
and you will see the effect of a parachute in miniature : but
this effect is very different from that of the paper wings ; the
parachute sinks gradually down in a •perpendicular line, whilst
the wings dart, forwards to the distance of several yards.

I have met with persons who have boldly asserted that it
is impossible for a man to exert sufficient strength to raise
himself up into the air by mechanical means alone ; but the
rashness and fallacy of such an assertion is completely refuted
and exposed by Mr. Degen, in Vienna, who has very lately
actually ascended into the air, to a considerable height, by
sitting in a machine and giving action to two parachutes ; and
had he properly understood the principles of birds’ wings, and

TEEATI8E UPON THE AET OF FLYING.

considered the astonishing power in the reaction of the air,
which may be increased in proportion to any force exerted upon
it, ad infinitum, and possessed a complete knowledge of the
principles upon which it enables birds to fly, he would have
chose wings and not parachutes, and might then have accom¬
plished flying in perfection *

There is no doubt that, by large parachutes, worked by
a mechanical power, a man may raise himself from the ground
to a considerable height ; but that cannot be properly called
flying, because as the compressed air rushes from underneath
the parachutes, to regain its equilibrium on all sides alike, there
will be no projectile motion effected, without which there can be
no command or steerage, and in such case the whole apparatus
will be driven which ever way the wind impels it ; I therefore
cannot give credit to that part of the account of M. Degen’s
performance which asserts that he flew in various directions,
although I can readily believe in his having raised himself into
the air, and think that great praise is due to him. I do not
believe it possible, upon his plan, that he could have gone in
any other direction than with the wind ; but with a pair of
wings constructed and worked according to the natural principles
of flying, a projectile motion is obtained in as perfect a manner
as buoyancy, both of which must be accomplished before we can

* M. Degen, a watchmaker of Vienna, has invented a machine by
which a person may raise himself into the air. It is formed of two
parachutes, of taffeta, which may be folded up or extended at pleasure,
and the person who moves them is placed in the centre. M. Degen has
made several public experiments, and rose to the height of fifty-four feet,
flying, in various directions, with the celerity of a bird. A subscription
has been opened at Vienna to enable the inventor to prosecute his
discoveries. — Vide the Monthly Magazine for September, 1809.

TREATISE UPON THE ART OF FLYING.

have the benefit and pleasure of flying with steerage, and that
upon the following plan only, viz. : —

Make a car of as light materials as possible, but with
sufficient strength to support a man in it ; provide a pair of
wings of about eight feet each in length, let them be horizontally
expanded, and fastened upon the top edge on each side of the
car, with two joints each, so as to admit of a vertical motion
to the wings, which motion may be effected by a man sitting
and working an upright lever in the middle of the car ; a tail
of about seven or eight feet long, and the same breadth at its
extremity, must be fixed to the hinder part of the car, and
spread out flat to the horizon id the same manner as we see
the tails of birds.

The grebes, by their manner of flying, evince that the
most important use of a bird’s tail is to support the posterior
weight of the body ; for the Creator having left the whole of
this class of birds, of which we have five different species,
indigenous in this country, all totally destitute of any portion
of a tail, they are, consequently, always seen when flying to
have their bodies hanging down nearly in a perpendicular
direction, and appear to fly with great difficulty ; but this
impediment in flying is of little consequence to them, their
organization being perfectly adapted to their mode of living.
They find their subsistence in lakes and pools, wherein they
are incessantly diving, and, of course, are not obliged to fly
until those places are frozen up, when they are compelled to
flutter off, as well as they are able, in search of some spring or
swamp which is not affected by frost, where they find a tem¬
porary subsistence until their favourite lakes are relieved from
a surface of ice ; they then return to their former haunts, where
they again seem quite in their element. Here we find a class

TBEATI8E UPON THE AST OF FLYIN0.

of birds, owing to their want of tails, possessing the power of
flight in a very imperfect degree, compared with some birds.
It also may be observed that birds having extraordinary large
tails, as the magpie for instance, do not fly in the best manner ;
none of these birds possess what seems to constitute the
excellence of flying, viz., soaring and reposing upon the air ;
this can only be effected when the weight of the body is upon
an equipoise in the centre of the wings and tail, each bearing
up its due proportion, and the expansion altogether so large,
as to bring the whole weight nearly in equilibrium with the
atmosphere. This must be properly attended to in the con¬
struction of a flying machine.

To give a further security to the power of suspension, a
sail of an equilateral triangle may be spread horizontally over
the man's head, supported by a small light mast or bowsprit,
at the height of three or four feet above the car ; the sail must
be expanded and fixed to the mast by a very light yard,
presenting the base of the sail to the head of the car, with the
opposite point towards the tail, and there fastened with a cord
to another small bowsprit ; this sail will be a protection, if large
enough, in case of any accident occurring to the machine ; it
will then prevent the man from being precipitated to the ground
in a manner similar to a parachute. I only have mentioned
this sail that it may be resorted to if it be found necessary in
a long voyage ; the first experiment I would try without it.

A coachmaker is accustomed to make strong work with
little weight of materials ; he, therefore, would be the most
proper person to make a machine of this kind. The man must
sit in the middle, between the wings and the tail, so as to be
a little behind the centre of gravity, for the purpose of causing
a little preponderance of weight to act upon the back edge of

TBEATI8E UPON THE ABT OF FLYING.

the wings ; for if there be not, in some degree, more weight
behind than before, when the compressed air is making a
resistance against the underside and back edges of the wings,
where it rushes upwards again, causing a great reaction, it
would, of course elevate the hinder part of the car too much.

The wings and the tail should be made of silk, very
compactly woven, and as impervious to the air as possible.
The silk which the wings are formed of, should be laid on in
separate broad slips,* and should open to admit the air to pass
through as the wings move up. and close together again as they
come down, in the same manner as I have described the action
of the quill feathers in the wings of birds ; although, upon the
experiment being tried, this method may not be found so
absolutely requisite, for we see flying squirrels, bats, butterflies,
beetles, flying fish, &c., with wings formed of compact mem¬
branes, all flying exceedingly well. The Madagascar bat has
a body the size of a rabbit, with wings four feet long, formed
of entire membranes, and, although so large, it can fly as well
as our little native bats ; therefore it is possible that a pair of
artificial wings may be formed without any valves, and yet
answer equally well ; but this can only be determined by actual
trial.

It is necessary to observe that the car in which the man
is to sit must be entirely covered on the outside with silk or
very thin leather, and along each side of the car the silk or
leather must be united to the base of the wings, to prevent,

* The tail feathers of turkies laid close and parallel to each other,
and fast sewed upon eight pieces of strong riband, so as to form the same
number of slips, then extended in the wing and well braced, would per¬
haps answer the purpose much better.

TREATISE UPON THE ART OF FLYING.

•57

as much as possible, the air from escaping any where but from
the back edges of the wings : should that be neglected, when
the air is compressed by the wings being struck downwards, it
will rush upwards through the car and thereby fail of giving
that" resistance against the underside of the wings which is
necessary for the purpose of effecting buoyancy and progression.

I think that the shafts of the wings and tail would answer
the purpose in the best manner, if they were each of them
made of six long slips of thin whalebone, dressed tapering to a
point, then wrapped together in a round form with small twine
from end to end, and filled with cork along the inside. By
making them in this manner they would spring against the air,
would be very light, and so strong that it would be impossible
to break them with the power or weight of any one person.
By forming them as above we shall humbly imitate the shaft
of a quill feather, which is composed of a thin homy shell,
containing a delicate light pith along the inside.

I here recommend my readers to particularly observe that
a main point in this treatise is that they should not overlook
the importance of the knowledge of the reaction of the air
against the underside and back edges of the wings, for this is
what causes the projectile motion, which is indisputably proved
by the flying of my paper wings across a room, and which I
will further illustrate by the flight of birds, mill sails, &c.

I have frequently conversed with persons about the art of
flying by mechanical means, and generally found them disposed
to treat the idea with ridicule. I have asked them if they
knew how birds were enabled to fly, and they mostly answered
me nearly in the following manner : that birds could fly
because it was natural to them, that they we’ o covered with

TBEATI8E UPON THE AST OF FLYING.

feathers, which were such light materials as to help them to
fly, and that their wings are properly adapted for flying. This
was as far as they could explain, which proved that all they
knew on this subject amounted to nothing. They generally
seemed to indulge an idea that there was something in the
flight of birds either supernatural or incomprehensible ; but I
hope my readers will be convinced, by this little treatise, that
the art of flying is as truly mechanical as the art of rowing a
boat.

I will here further illustrate how flying is effected. The
air, when struck upon by wings, produces an effect by its
reaction against the underside and back edges, similar to that
which is caused by the wind blowing with sufficient force
against a mill-sail, when it rushes off on one side, and impels
the sail to move, with this difference only, that the sail, being
fastened at one end to an axis, is made to revolve, whilst the
bird, being at full liberty in the air, is caused, by the expansive
power of the air acting with a resisting force against the back
edges of the wings, to glide forward in a right line.

Most of my readers, I think, will acknowledge the great
elastic power of the wind, as it is manifested by the sailing of
ships and the revolving of mill-sails ; these effects are produced
by the wind being compressed against the sails from its own
natural motion and force ; but the effect the air has against
the wings or sails of birds is produced by its being compressed,
with them striking vertically upon it ; and the larger they are
made the greater quantity of air is compressed, by which means
is caused a more- powerful reaction, and consequently a more
effectual buoyancy and progression. From this cause all the
birds whose wings are very large in proportion to their weight are
able to fly with the least exertion imaginable, whilst birds with

TREATISE UPON THE ART OF FLYING.

very small wings are obliged to use very great labour indeed ;
this being demonstrated by the examination of the dimensions
of birds’ wings and their specific gravity, and by observing their
different methods of flying.

I have often been delighted with the striking conviction
that Supreme wisdom alone could have so nicely adjusted all
the various internal and external organization of the vast
number of different species of birds, to their diversified wants
and modes of living ; but it is only necessary to observe here
that all those which are under the greatest necessity of flying
are provided with the longest and best proportion of wings and
tails, and are consequently able to fly in the best manner, and
those which need them less* have them more limited, and are
therefore less capable of flying, as if the all-wise Creator had
set limits to their powers of flight, that they might not go out
of their respective elements.

Although I think that a pair of wings seven or eight feet
each in length would be sufficient, still, if I could make it
convenient to try the experiment of flying, and were not pre¬
vented, as I am, by a chain of untoward and uncontrollable
circumstances, I would cause the wings to be made of as large
dimensions as I could possibly move with ease.

I observe amongst the aquatic birds that the auks, guille¬
mots, divers, &c., have such remarkably small narrow wings
that they would be utterly incapable of keeping themselves up
in the air if it were not for an exertion which they are obliged
to make in the extreme. Their wings are moved with such
rapidity as to be with difficulty discerned. In this we see the
economy of the all-wise Creator, for according to their habits
and appetites they have very little occasion to fly at any time,

TREATISE UPON THE ART OF FLYING.

except during the time of incubation, when they have to ascend
the most inaccessible rocks and cliffs they meet with along the
sea shore, where they breed and rear their young ; all the rest
of their time they pass on or in the water, swimming and
diving for their food.

All the gallinaceous class of birds have very short concave
wings, which they strike with great exertion ; they also, in
general, have but little occasion to fly ; their food, which consists
principally of grain and seeds, being spontaneously scattered
over the earth, they are almost constantly upon their legs,
running about to pick it up, and seldom fly but to avoid danger.

On the other hand, rapacious birds, who appetites induce
them to be the greatest part of their time upon the wing, in
search of a subsistence which is very precarious (as every
inferior bird, &c., to which they direct their sanguinary attacks,
from that love of existence which God has so strongly implanted
in all His creatures, will use its utmost skill and activity to
elude its destroyer), are much better accommodated, having
wings of large dimensions they can repose upon the air, and
project themselves forward with a gentle wafting. This is the
class of birds I would copy from in the construction of a
machine for artificial flying. The kite or glead, P, B, Z,
(or milvus from Lin.,) is the best natural specimen that we can
find in the British ornithology ; this bird has very large flat
wings, with a large forked tail, and flies with the least exertion,
I believe, of any bird in the creation.

All the hyrundo class of birds are almost constantly flying ;
they all have bodies of little weight, have large flat wings, and
fly with great ease. The goat-sucker, which is a species of
nocturnal swallow, is admirably constructed for flying with
facility.

TBEATISE UPON THE ART OF FLYING.

As I have mentioned aquatic birds, I will here take the
opportunity of execrating, with all the indignation of my soul,
that savage and brutal amusement whiph they bring to my mind,
and which so many persons frequently practice and take delight
in ; I mean the shooting these harmless and inoffensive birds.
Many are the parties who resort to Flamborough-head, for no
other purpose than gratifying their vanity by making a display
of their dexterity in shooting, and causing all the havock they
possibly can amongst the poor inoffensive birds. Barren must
be their minds, and callous their feelings, who can take pleasure
in destroying these innocent creatures, which are not in the
smallest degree offensive to man when they are living, nor of
the least service to him when killed. If these gentlemen could
eat them when they have done shooting, that would be some
excuse ; but as their flesh is very rancid these wanton barbarians
have no relish for their game. I wish their humanity was as
nice as their appetites, they would then not find delight in
merely shooting them for sport and cruelty, leaving them, some
killed and others wounded, floating on the surface of the sea,
whilst their helpless young ones must consequently perish with
hunger upon the shelvings of the rocks. Such amusements,
surely, are not becoming rational beings, but may give pleasure
to semi-rationals.

In the months of May and June these birds, which, during
the rest of their time are dispersed over various parts of the
ocean, are brought by one of the great impulses of nature to
assemble at Flamborough-head in myriads, producing a throng,
upon a great extent of cliff, similar to what we see in miniature
in the front of a bee-hive, on a fine summer’s day, when there
is a perpetual egress and ingress of thousands.

A person who has never seen such a sight, and is capable

TREATISE UPON THE ART OF FLTTNO.

of deriving pleasure from contemplating the economy and the
works of nature, may find an exquisite gratification in paying
a visit, at this season of the year, to Flamborough-head,
without having recourse to wanton acts of cruelty. Will there
ever come upon the earth a generation of men who will despise
all pleasures that are either unreasonable or inhuman ?

Reason and humanity constitute the only permanent basis
of all human happiness, and the real honour and true glory of
man ! without which he is but a compound of folly and mad¬
ness, and is too often a vile mischievous brute. By a disregard
and contempt of these two divine guides families and nations
become distracted and are made miserable, as we have too
amply witnessed in the deplorable and wretched state in which
-Europe has been so long afflicted, where the appetite of the
cannibal has only been wanting to complete the brutality of
civilized nations. But I am departing too much from my
original subject ; I will withdraw my pen from this sickening
view of poor, frail, erring, human nature !

After having described how to construct a machine to fly
in, which, like the swift or great black martin (apus, Lin.),
cannot fly from the surface of the ground, but must have an
elevation to rise from, it becomes necessary that I should give
directions how it may be made to ascend. Set two tressels
fast upon the ground, one six feet high and the other four-and-
a-half, at twelve feet distance from each other ; then lay upon
them two or three planks, which will form a stage with an
oblique plane, upon which the car must be placed, with its head
pointing to the higher end of the stage.

A person may then get into the car, and sit a little behind
the centre of gravity, which must be adjusted before the car is

TREATISE UPON THE ART OF FLYINO.

placed there ; being thus elevated he will have depth enough
on each side of the car to admit of his wings striking upon the
air. He must then push the lever forward about eighteen
inches from its perpendicular line, the tips of the wings will
then rise three feet and a half above the level of their joints ;
he must then, with a brisk exertion, pull the lever backwards
eighteen inches past the perpendicular line, and the tips of the
wings will be struck downwards, passing through an arch of
seven feet and suddenly driving down and compressing the air
in that arch, part of which will escape past the back edge of
the wings (as I have described before), making at the same
time a reaction which will push the wings forward : and as
the car and the wings are first placed on an oblique plane,
they will be impelled forwards, making an oblique ascent.
The projectile impulse will naturally force the machine
upwards in any angle in which the plane of the wings is laid,
somewhat similar to what may be observed in the raising of a
common paper kite, except in a right angle, or perpendicular
line ; but the nearer the angle of ascent inclines to the line of
the horizon, the easier will the machine be found to ascend.
I believe pigeons can ascend very near in a perpendicular line,
but such an ascent would be too incommodious for artificial
flying.

When the car is brought to a sufficient altitude to clear
the tops of hills, trees, buildings, &c., the man, by sitting a
little forward on his seat, will then bring the wings upon an
horizontal plane, and by continuing the action of the wings he
will be impelled forwards in that direction. To descend, he
must desist from striking the wings, and hold them on a level
with their joints ; the car will then gradually come down, and
when it is within five or six feet of the ground, the man must
instantly strike the wings downwards, and sit as far back as he

TREATISE UPON THE ART OF FLYING.

can ; he will by this means check the projectile force, and
cause the car to alight very gently with a retrograde motion.
The car, when up in the air, may be made to turn to the right
or the left, merely by the man inclining the weight of his body
to one side.

When I have seen a man sitting in a chair upon a tight
rope, with a table before him, spread over with decanters,
glasses, &c., &c., and, by his dexterity alone, be able to keep
himself and all his accommodations exactly balanced there,
while he sat smoaking his pipe, apparently at perfect ease ;
I have been induced to consider the art of managing a flying
machine, compared with such a surprizing display of human
dexterity, to be very simple ; and see no reason why men
should not become as expert in navigating the air as the sea.

As some of my readers, who may have little regard for
any thing but the utile, may be induced to ask, what use will
flying be of, when it is attained ? I beg leave, in the way of
reply, to give the following hints : — I hope it will be granted
that flying will be of great use, if by such means we can have
our letters, newspapers, &c., conveyed to any part of the
kingdom at the rate of forty or fifty miles in an hour ; or if
that numerous class of mercantile agents who are now denomi-
ted riders, henceforth be enabled to glide through the air with
great expedition, in flying machines ; or if a man, by such
means, can take a rope to any mariners in distress along the
sea coast, and thereby become the happy instrument of saving
their lives ; and if the circumnavigator be able to quit his
ship, fly and explore the interior parts of a new discovered
island, free from the annoyance and hostilities of its rude
inhabitants — but it would be tedious to enumerate all the
uses to which artificial flying may be applied : it is obvious

TREATISE UPON THE ART OF FLYING.

enough, that when one man is enabled to fly, thousands may
do the same, either on business or pleasure. It may tend
greatly to reduce the vast number of horses kept in this
kingdom, and by that means a very great quantity of land,
which is taken up at present in growing hay, oats, and beans,
for the support of these quadrupeds, might be then cultivated
for the increase of our national stock of subsistence for the
population ; and I think it is evident that we have great
occasion to reduce the superfluous number of those animals,
and to employ all the land we possibly can to grow corn, &c.,
for our own subsistence. It is not improbable, that some
persons will ask, if flying and all this can be accomplished ; to
which I answer, that if my scheme for attaining the art be
deemed a rational one, as I hope it will, I think we certainly
ought to try the experiment.

After the perusal of this work, I hope my readers will be
fully convinced, that all attempts which have been hitherto
made in the art of flying have failed, not in consequence of
the art being impracticable, but from the natural science of
flying having never yet been fully understood. All that has
ever been written, and all the experiments that have ever been
made towards attaining a knowledge of artificial flying by
mechanical means, display a chaos of unsettled thoughts very
wide and deficient of the principles of nature ; but I hope it
will be granted that I have clearly discovered and demonstrated
the whole of those principles upon which flying depends,
particularly the cause of the projectile motion of birds. This
is a discovery of the greatest importance, for as the air is
continually acting, in the manner I have described, against the
back edges of the wings, and thereby impelling the bird
forwards with great force, it positively has as much tendency to
overcome specific gravity as the expansion of the wings has.

6fi TREATISE UPON THE ART OF FLYING.

This is a fact demonstrated very clearly by my paper wings.,
and by the manner of flying peculiar to some birds,, particularly
the woodpeckers. When one of these extraordinary birds has
struck its wings once or twice upon the air, and thereby
produced a projectile impulse sufficient to force it forward to a
considerable distance, it instantly contracts its wings as close to
its sides as when perched on a bough, and continues flying
several yards with its wings kept close in that position, until
the impulse is abating; it then throws out its wings again,
gives another stroke or two to renew the impulse, shuts them up,
and is again driven forward ; thus continuing to fly by distinct
and separate projectile impulses alone. Here then we see the
great importance of a true knowledge of the cause of the
projectile motion of birds, for this surprising bird does not
depend upon a continued expansion of wings to keep itself up
in the air, but is kept up and carried forward by the projectile
force alone !

The green woodpecker is about the size of a pigeon, and
as it is very common in every part of England where wood
abounds, many of my readers may have an opportunity of
observing its curious method of flying ; the same may be
observed of the beautiful little goldfinch, and of linnets.
Here the physico-theologist, who is accustomed to contemplate
the wisdom of God in all His works, might be led to infer
that He has caused this deviation from the general method of
flying, in order to demonstrate to us the effect of the projectile
force, and that it is one of the greatest essentials in the art of
flying, and perfectly distinct from and independent of the
continued expansion of wings.

When we see pigeons flying upwards in the angle of sixty
or seventy, as we do every day, from the streets to the tops of

TREATISE UPON THE ART OF FLYING (>7

houses, with the plane of their wings parallel to the line of
their ascent, I think they prove in a satisfactory manner the
great effect of the projectile force ; for without we admit this
to be the cause of their ascending in such angles, how can we
possibly account for it in any other way, upon rational
principles ?

A stone thrown by the hand, and a ball ejected from the
mouth of a cannon, are made to overcome specific gravity, and
fly to a great distance ; we all know that these are not kept up
by wings, but entirely by the projectile force. In fact, it is by
the air being made continually to push the bird forwards,
which constitutes the main cause of flying.

We must attribute to a total ignorance of the funda¬
mental principles, that the art of flying has not been brought
hitherto into common practice ; for an art, so practicable as it
is, must at any period of time have soon succeeded a discovery,
such as I have made ; and now that the art appears so very
attainable, I hope that every friend to arts and sciences will
acknowledge that it ought to have a fair trial.

I shall now conclude my treatise on flying with an appeal
to the candour and good sense of my readers, whether the
arguments I have used, and the principles upon which I have
insisted the art of flying may be accomplished, are not such as
give it a just claim to their approbation ; for I think I may
affirm, without being accused of arrogance, that the art of flying
has never before been treated of upon such rational and
scientific principles.*

* I will here take the liberty of communicating a few hints, which
I conceive to be of importance to the aerostatic science. Now that we

TREATISE UPON THE ART OF FLYING.

Having now submitted to the good sense of my country¬
men the whole of what I intended on the subject of flying,
I, for the present, most respectfully take my leave of them,
indulging a hope that the prediction of Bishop Wilkins,
expressed in a former page, will soon be verified, and trusting

know the true cause of the projectile motion of birds, and I having
suggested a plan for producing the same effect by artificial means, we
may be able to accomplish what Messrs. Roberts, Blanchard, and others
attempted to do, but in vain, entirely from their not possessing a
knowledge of this mystery of nature. I am alluding to the steerage of
balloons, which they endeavoured, with great labour, to attain, by
striking a number of oars horizontal 1 y against the air ; and if we do but
take into consideration that the balloon was constantly flying from the
air against which they were striking, it does not seem probable that they
could, by such means, produce the effect they aimed at.

But if we make a car from the plan which I have laid down in this
treatise, and upon a scale large enough to admit of one of Messrs. Mead
and Co.’s new invented revolving steam engines, to move the lever with,
we then can work, in a vertical direction , a pair of very large wings, which
would produce a projectile force sufficient to impel the balloon forwards
in any point of the compass to which we might incline it ; and by having
a large tail fixed to the car, in an universal joint, we should be able to
give it any inclination whatever ; and when we have thus effected
a perfect steerage to balloons, we shall be able to convey a number of
passengers to any place of destination with accuracy and safety. But
for this kind of navigation the balloon must be much smaller than usual,
and perfectly spherical, and the gas should be kept in such a degree as
not to have too great a tendency to ascend — it should be so regulated as
to float in equilibrium with the atmosphere ; the aeronauts could then
lceep the machine at a moderate height — from fifty to a hundred feet
would be high enough for ordinary sailing, and if it was found to be
inclining too much upwards, it might be counteracted by holding the
tail in a descending direction. One of Mr. Mead’s patent steam engines
can be made with a one horse power, or equal to the strength of eight or
ten men, that will not weigh more than eight stone ; and will stand in
the small space of four feet by two, with the boiler and all the apparatus
belonging to it.

treatise upon the art of flying.

that I shall not be disappointed in the opinion I entertain
respecting the patronage which they will extend towards the
invention now laid before them. Encouraged by the public,
I shall not abandon my purpose of making still further
exertions to advance and complete an art, the discovery of the
true principles of which, I trust, I can with verity affirm to be
exclusively my own.

AERONAUTICAL SOCIETY

CONCLUDING REMARKS.

We have presented our readers in this Report with a
reprint of a Pamphlet by Mr. Walker, a Portrait Painter of
Hull, upon which some further remarks are here offered.

This essay, considering the time when it was written, is
remarkable, inasmuch as the Author ignores the balloon as an
available means of flight, or of traversing the air in any
direction at will. His ideas of success are entirely based upon
mechanical flight obtained upon the same principles and action
as that of birds and animals.

Mr. Walker says that the hold upon the air is always in
proportion to the dimensions of the wings. Now there is a
necessary condition attached to the support of a bird in flight
which tends to equalize the great disparity which exists
between the weight and wing surface of various birds, viz., the
arc of vibration, and the rapidity with which the strokes are
delivered. Take for instance two familiar examples — the rook
and the pheasant. The weights and measurements of both
birds, taken for this purpose, are as follows : —

The rook, l^lbs., wing surface 152 square inches, a
surface which appears to support the bird very often, in a
lengthened gliding flight, without any wing motion.

The pheasant, just over 31bs., wing surface 137 sq. inches.
It is therefore impossible for this bird to use its wings as fixed
planes and glide like the rook. What it really does is to work
its wings with such rapidity that the vibration produces an
audible effect, and shows the great muscular force possessed
by the bird, due to its much greater weight. It is nearly three

OF GREAT BRITAIN.

times the weight of the rook, and has 15 square inches less
wing surface.

Mr. Walker next alludes to the necessity that the quill
feathers should separate and open to let the upper air pass
through the wings, but he afterwards qualifies this assertion,
and thinks that a pair of artificial wings may be formed without
any valves and yet answer the purpose equally well. Certain
it is that flight, after the manner of a bird, is now attained by
mechanical models without any opening out of the wing feathers
in the up stroke, and that an artificial wing, covered with a
continuous membrane, is effective in the upward stroke in
propulsion.

This may be tested by waving a wing up and down whilst
standing or sitting upon a pivoted stool, say a music stool.

As all impulse applied to a body in the air tends to over¬
come the action of gravity, so in this sense the upward stroke
has a supporting effect.

The Author here also anticipates the published results
of modern researches into the mechanical condition of flight,
for he says that forward speed “ positively has as much tendency
to overcome specific gravity as the expansion of the wings has.”

He also gives us an example of some calculations which
he had made respecting the relative wing surface of various
birds, which correspond with some of M. de Lucy’s recent con¬
clusions, and which evidence his possession of much shrewd
observation beyond the sphere of his avocation, that of a
Portrait Painter. The result of his argument relative to the
condor, its normal weight and extent of its wing, and its
capability of carrying off a sheep, is, if the facts be not
exaggerated, entitled to consideration.

Although we have reprinted the Pamphlet it is not thought
necessary to reproduce the accompanying plates, which seem
to show, by a certain clumsiness in the construction, that the

AfiBONAUTIOAL society

Author was deficient in the mechanical skill requisite to cany
his ideas into successful practice.

A man may be perfectly competent to grasp the truth
relative to all the actual requirements for obtaining a fulcrum
upon the air. and yet grievously fail in adapting such an
apparatus as may fulfil these conditions.

We do not say that this remark particularly applies to
Mr. Walker ; but, as a fact, every inventor will attack the
problem in his own way. His apparatus will be evolved from
his own perception of the difficulties to be overcome, and will be
more or less a failure or more or less a success, according to his
mechanical skill. Generally speaking all other inventions than
his own are at least — amusing !

When the subject of aerial navigation is only mentioned
in the presence of ordinary persons, it is received as though the
believers in its possibility are fit subjects for lunatic asylums.
That it is simply a mode of transit which can be accomplished
by carefully devised means and appliances, and an expenditure
of an amount of cash which is altogether insignificant when
compared with the importance of the subject, is the established
belief of many ; and in the midst of the general want of know¬
ledge which exists in connection therewith, it is most refreshing
to take up a work like “Aerial Navigation,”* and to find the
subject treated not only without prejudice, but in a most
comprehensive and philosophical manner. In fact, before going
through many pages, the reader finds that he is imbibing the
outcome of a mind of gigantic proportions, whose penetrative
powers and felicity of resource are almost unbounded : and in
the midst of his pursuit of this one grand subject the Author
makes sudden darts into other subjects in such a masterly

* “Aerial Navigation,” by the late Charles Blachford Mansfield, M.A.,
edited by his Brother, Robert Blachford Mansfield, B.A. — Macmillan
and Co. ; 1877. — Price 1 Ox. 6<J.

OF GREAT BRITAIN.

manner as to greatly enhance one’s estimate of his capabilities.
Cut off by a sad accident in February, 1855, as the Author
was, in the height of his bodily and mental vigour, it is clear,
from this unfinished work, that, had he lived, he would have
been largely instrumental, even if not himself successful, in
solving this problem.

The Author goes into the subject in a most exhaustive
manner, scarcely leaving a point untouched.' The work is
resolved into two great divisions, each of which is subdivided
into fifteen heads, and an addition of appendices, under six
heads, completes the work.

The first division of the work states the “ difficulties ”
which surround the problem, as follows : —

Chap. 1. Introductory.

„ 2. The problem of flying.

„ 3. The impossibility of propelling balloons, and

the first difficulty in aerial navigation — the
application of force.

„ 4. The second difficulty — the gas -vessel; its

stiffness.

„ 5. The third difficulty — the gas-vessel ; its firm¬

ness.

„ 6. The fourth difficulty — the rising and falling of

the air-craft.

„ 7. The gas-vessel — the question of shape.

,, 8. The gas-vessel — the question of material.

„ 9. The gas-vessel — the question of contents.

., 10. The air-craft — the question of floatage.

„ 11. The fifth difficulty — the air-craft ; the question
of level.

„ 12. The question of power.

„ 13. The question of waftage.

,. 14. The question of anchorage.

„ 15. Conclusion. Summary of contents.

K K

AERONAUTICAL SOCIETY

The second part of the work consists of “ hints for the
solution of the problem,” and goes over each of the above
fifteen heads in a highly-instructive and careful manner.

Chapter 1, part the first, is introductory. The Author
attacks the opinions expressed in the then later edition of the
“ Encyclopaedia Britannica ; ” and we may here mention that
the late edition of that standard work, written since the death
of our Author, omits all the absurd notions which were con¬
tained in the former edition, and thus fully confirms the
justice of our Author’s remarks.

The “ problem of flying ” is clearly and forcibly stated.
In tackling the question whether a man may or may not have
sufficient muscular power to fly, the following original, though
perhaps questionable, way of treating the subject may be quoted
(pages 25 to 28) : —

“ It would seem a waste of words to argue that a man can
raise himself by his legs, without going up a ladder (which is
in fact a flight in which support is taken from the rundles
instead of from the air). No one can advance a step on level
ground without lifting his entire weight. Each step (starting
from the erect position) commences by a fall forwards, which
is arrested by the advancing foot as it reaches the ground.
Now, if there is a fall, it must be followed by an equal rise,
which is effected by the leg that is left behind, which pushes
his body forwards and upwards till the centre of gravity recovers
its former height. The body is thus raised in walking chiefly
by the muscles of the calf, extending the foot and opening the
angle between the instep and the skin. The leg that did this
part of the work, and was left behind, is then lifted by itself
and brought forward to receive the next fall in its turn. The
longer the step taken the greater the height through which
the walker falls, and the greater therefore the height through
which he must raise himself. I shall not overrate the height

OE GEEAT BRITAIN.

through which the centre of gravity of the body falls and is
lifted again, if I assume it at three inches for every complete
step of a yard. If this be so, in walking a mile a man will
have lifted himself through 3 + 1700 inches = 146‘6 yards,
so that his mile’s work may be represented as equivalent, so
far as his legs are concerned, to a flight directly upwards to a
height of about 146 yards. . . . The enquiry now arises —

Can the power thus available be applied to the air without such
loss as to make it useless in practice ? This I do not undertake
to demonstrate, but shall leave the question to the advocates
of mechanical flying. In attempting to solve this problem,
however, provision must be made that, in case of an accident,
the flyer shall not at once fall headlong.”

Chapter 3, upon “ the impossibility of propelling balloons,
and the first difficulty in aerial navigation,” is well handled.
The following, from pages 34 and 35, will interest our
readers : —

“ The balloon has become a means of making a livelihood,
which held out to needy men, generally innocent of science, a
prospect of acquiring a competency, and perhaps wealth, with
the addition of notoriety. While then they have been racing
with each other up to the clouds for mammon or a maintenance,
it was not likely that they could stop to consider whether it
were possible to travel together upon a level course. What
again could be done by isolated contrivers ? One describes his
device in a Journal or writes a Pamphlet ; another criticises
his plan, picks out some absurdity, and proposes a rival crotchet
of his own, with which some one else finds fault in turn. One
burdens himself and his scheme with letters patent. Another
pompously declares he has solved the great problem, but will
not make revelation thereof till he is well paid ; and the men
of capital who, each by himself, might be able to do but little
to favor the growth of an useful art, however well disposed

AERONAUTICAL SOCIETY

to do so, are either unwilling to unite their- means, exfcept for
the purpose of increasing them, or have been discouraged by
the repeated failure of former individual schemes.

“But to return to propulsion. I have said that to propel
the balloon is simply impossible. This has long been apparent
to mechanical minds that did not happen to be enthusiastic
about aeronautics, and has been pointed out over and over again,
and the difficulty has been supposed to be an insurmountable
barrier to any attempts to direct gas-vessels of any form. That
which is an impossibility for the balloon is still a serious
difficulty for gas- vessels of a more reasonable shape.”

The above extracts will give some idea of the work, and
we would strongly recommend those of our readers who con¬
template making experiments to carefully study this very
valuable contribution to the science of aerial navigation.

It is now an established fact that models of very different
forms have been made to fly by means of a stored-up power
contained within themselves, even when this power is employed
for obtaining a support or abutment upon the air by very
different modes of application. Those who will dogmatically
assert that flight is impossible for man, may say that it is
apparent that the power required and employed to support these
models of lath and fabric is enormous for the weight, and
scarcely affords any hope of being able to solve the problem ;
but then it can be argued that this power is not a fixed
and definite one in all conditions. On the contrary, there is
perhaps no application of power in which the extremes of much
or little, are so widely different, according to the ways and
means by which it is utilized. So little advance have we made
in this problem, that perhaps in the very models that are now
employed to demonstrate the possibility of a form of mechanical
flight — and do so unmistakably — in reality effect their support
and progress in air with the maximum expenditure of power t

OF GREAT BRITAIN.

t (

were it otherwise not much scope would be left for improve¬
ments. The minimum of power requisite has yet to be
arrived at, and even theory on this subject has not been
sufficiently advanced, to the present date, to afford a solution
of the question.

A&RONATTTICAL SOCIETY

MEMBERS.

Alexander, A., M.A., C.E., Cyclops Steel and Iron Works, Sheffield ;
of the Council

Anderson, Capt. A. Dunlop, 23rd Punjab Pioneers, 21, Lennox Street,
Edinburgh

Arbuthnot, H. Gough, 40, Prince's Gate, s.w.

Argyll, the Duke of, F.R.S. ; President of the Council
Armour, James, C.E., Gateshead

Avery, W. Bailey, Norfolk Road, Edgbaston, Birmingham
Ballard, Stephen, C.E., Colwall, Great Malvern
Barrett, Frederick, Langley House, Grove Lane, Camberwell, b.e.
Baxter, Richard, F.R.G.S., 19, Leinster Gardens, w.

Bell, Charles W., Roche Court, near Salisbury
Bennett, T. J., 20, Little Clarendon Street, Oxford
Biddle, Dr., Kingston-on-Thames
Blass, E., C.E., Cleve, Prussia
Borthwick, Lord, 35, Hertford Street, May Fair
Bourne, John Fred., C.E., Louth, and Civil Service Club
Brearey, Fred. W., Maidenstone Hill, Blackheath ; of the Council, and
Honorary Secretary

Bright, Sir Chas. Tilston, F.R.A.S., 26, Duke St, Westminster, s.w. ;
of the Council

Brooke, Charles, M.A., F.R.S., 16, Fitzroy Square ; of the Council
Brown, David Stephens, The Norton, Tenby, Pembrokeshire
Browning, John, F.R.A.S., 63, Strand ; of the Council
Brownjohn, William Wade, Jun., United Service Club
Burnaby, Captain, Royal Horse Guards ; of the Council
Burrell, Edward, The Hermitage, 7, Melina Place, St. John’s Wood
Burton, Rev. Roger Taylor, M.A., The Vicarage, Great Tey, Kelvedon,
Essex

OF GREAT BRITAIN.

Chaplin, James C., 4, Garden Court, Temple
Chatto, Andrew, 74, Piccadilly

Clare, Walter F., Rivercourt Lodge Upper Mall, Hammersmith
Crestadoro, Dr., Free Libraries, Manchester
Davies, Charles, 47, Pall Mall

Dawson, G. J. Crosbie, C.E., The Cliff, Preston, Lancashire
Deck, Arthur, King’s Parade, Cambridge

Decruz, E., Seetarampore Collieries, Raneegunge, Lower Bengal, India
Delane, John T., 16, Sergeant’s Inn, Fleet Street
De Satrustequi, Don Joaquin Marcos, Consul General de Espana,
21, Billiter Street

De Yilleneuve, Dr., Rue Lafayette 90, Paris

Dufferin, Earl of, 8, Grosvenor Square ; Vice-President of the Council
Elphinstone, Lord, 24, Carlton House Terrace

Frost, Edward P., J .P., West Wratting Hall, Linton, Cambridgeshire
Garrett, Captain, Clevedon Lodge, Reading

Glaisher, James, F.R.S., F.R.A.S., &c., Blackheath; of the Council
Gordon, R. Newton, 1, Bloomfield Road, w.

Greenway, Henry, M.R.C.S., Plymouth
Gbeetham, Thomas, 26, Bedford Row, w.c.

Grosvenor, Lord Richard, M.P., F.R.G.S., 76, Brook Street, w. ;
Vice-President of the Council

Hall, Alexander Lyons, F.R.G.S., 48, Blenheim Crescent, Notting Hill
Hamilton, J. Lawrence, M.R.C.S., 34, Gloucester Ter., Hyde Park, w.
Harper, J. E., 257, Southampton Street, Camberwell
Hay, Rear-Admiral Lord John, 149, Piccadilly ; of the Council
Jay, R. C., 89, Cornwall Road, Bayswater
Jennings, William, F.R.G.S., 13, Victoria Street
Knight, John, Oakhill, Hildenboro, Kent
Krueger, W. G., Downeville, Sierra County, California
Latham, Baldwin, C.E., 7, Westminster Chambers
Le Fevre, Wm. H., C. E., F. R.G. S., St. Antholin’s Chambers
26, Budge Row, Cannon Street, e.c. ; of the Council
Lilienthall, Otto, Albrecht St. 13, Berlin
Lindsay, Lord, 47, Brook Street, w.

Londonderry, the Marquis of, Londonderry House, Park Lane

AERONAUTICAL SOCIETY

Macdonald, Major-General, 27, Park Lane, w.

Manners, Lord John T., Guards’ Club, s.w.

Marriott, Frederick, San Francisco, California
Matthews, Edwin, 26, Bedford Row, w.c.

Maxwell, Captain R. J., Army and Navy Club, s.w.

Middleton, Henry, 11, Bateman Street, Cambridge
Morrieson, Colonel R., Oriental Club
Mot, Thomas, 37, Farringdon Street

Ofenheim, Victor R. Von, Schwarzenberg Strasse 18, Vienna
Ohren, Magnus, A.I.C.E., F.C.S., Lower Sydenham ; of the Council
Osler, Abraham Follett, F.R.S., South Bank, Edgbaston, Birmingham
Owen, Captain, R.A., 43, The Common, Woolwich
Penaud, Alphonse, 14, Rue Castellane, Paris
Perigal, Henry, Jun., 9, North Crescent, Bedford Square
Phillips, W. H., Linden Grove, Nunhead, s.e.

Risley, J. B., C.E., Brondeg, Ferryside, South Wales
Roberts, Major-General, 4, Hyde Park Terrace
Roberts, Major H. C., 48, Hereford Road, Bayswater
Senbcal, P., 261, Brompton Road, s.w.

Siemens, Dr. C. W., C.E., F.R.S., 12, Queen Anne’s Gate, Westminster

Spier, M. H., 15, Westbourne Park Terrace

Stringfellow, John, Chard, Somerset

Sutherland, the Duke of ; Vice-President of the Council

Temple r, Captain, Harrow

Thorman, A. J., 281, New Cross Road, s.e.

Tracey, The Honourable Henry Hanburt, Gregynog Newtown, Mont¬
gomeryshire

Walker, Charles Clement, Lilleshall Old Hall, Salop
Walker, Thomas, 24, Oxford Street, Birmingham
Wenham, F. H., C.E., V.P.R.M.S., 3, Gothic Villas, Warbeck Road,
Shepherd’s Bush, w. ; of the Council
Whittell, Charles, C.E., Sydney, Australia
Wright, Henry, Stafford House, St. James’ ; of the Council
Yorke, Pierce Wynne, Dyffryn Aled, Abergele

OP GREAT BRITAIN. SI

The following SPECIFICATIONS OF PATENTS

Are Presented to the Society by the Commissioners.

Date.

No.

1876.
Mar. 7.

924.

June 13.

2313.

Sept. 4.

3859.

Oct. 15.

3814.

Oct. 27.

3974.

Subject .

Patentee.

Improvements in and appertaining / H. Ballint.
to Machines for Aerial Navigation ^ J. W. Payner.

Balloons for Aerial Navigation —

Communicated by Count A.

Apraxine.

Machinery for Propelling and Guid- \
ing Vessels on land and through („ T n
air and water — Communicated by f ' ' addon

L. Brennan and W. Calvert ... )

An improved Military Apparatus \
or Aerial Battery — Communicated > C. O. Rogers.
by A. W. Gittens . . . )

Improvements in A£ro- Navigation
and in the construction arid use of
Aerostats, and in the Machinery
and Apparatus therefor which im¬
provements are in part applicable
to other purposes . .

Brannon.

BOOKS. PAMPHLETS. &c., RECEIVED.

Solution • CompUte ile la Navigation Aerienne — By the Author,

M. Perigeux.

Annual Report of the Board, of Repents of the Smithsonian Institution!

Washington! for 1875 — By the Regents.

Angus and Mack on the Air Path ; James Armour, C.E. — By the Author.
Catalogue of Special Loan Collection — By the Commissioners.

Angus and Mack on the Air Path, Part HI; James Armour, C.E. —

By the Author. ... ; _

The Monthly Numbers of L' Aeronaute — By M. i.E Pocteur de
Vili.eneuvk.

L L

J. H. STOREY,

ENG-I1TEER; <3& MODEL MAKER,

37, FARRINGDON STREET, E.C.,

Having been engaged for upwards of four years in making
the apparatus for Mr. Moy’s Experiments, can bring to bear
a large experience in constructing Models for experiments

in Aeronautics.

Reference by kind permission to Fred W. Brearey, Esq., Honorary
Secretary to the Aeronautical Society, Maidenstone Hill,
Blackheath, s.E.

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